Method for using water insoluble chemical additives with pulp and products made by said method

ABSTRACT

Pulp fibers can be treated with water insoluble chemical additives resulting in a minimal amount of unretained water insoluble chemical additives present after exposing the treated pulp fibers to process water, liquids, or solutions used in products. One embodiment of the present invention is a method for preparing chemically treated pulp fiber. A fiber slurry is created comprising process water and pulp fibers. The fiber slurry is transported to a web-forming apparatus of a pulp sheet machine thereby forming a wet fibrous web. The wet fibrous web is dried to a predetermined consistency thereby forming a dried fibrous web. The dried fibrous web is treated with a water insoluble chemical additive thereby forming a chemically treated dried fibrous web containing chemically treated pulp fibers. The chemically treated pulp fibers have an improved level of chemical retention of the water insoluble chemical additive and retain from between about 25 to about 100 percent of the applied amount of the water insoluble chemical additive when the chemically treated pulp fibers are exposed to a liquid, such as water. The chemically treated pulp fibers are used to form a fibrous non-woven material.

BACKGROUND OF THE INVENTION

[0001] Fibrous non-woven materials and fibrous non-woven compositematerials are widely used as products, or as components of products,such as wet-wipes because they may be manufactured inexpensively andmade to have specific characteristics. These products may bemanufactured so inexpensively that they may be viewed as disposable, asopposed to reusable.

[0002] One approach to making fibrous non-woven composite materials forwet-wipes is the use of homogeneous mixtures of materials such as airlaid webs of fibers mixed with cellulosic fibers or another absorbentmaterial. Other wet-wipes have been prepared by joining different typesof non-woven materials in a laminate or formed as a layered structure.These products may be prepared from plastic materials such as plasticsheets, films and non-woven webs, prepared by extrusion processes suchas, for example, slot film extrusion, blown bubble film extrusion,meltblowing of non-woven webs and spin bonding.

[0003] The non-woven materials and laminated non-woven materials thatare useful for consumer products should meet minimum product standardsfor strength, moisture level, size, flexibility, thickness, softness andtexture. However, if one of these parameters is changed this may affectanother of the parameters. Thus, a goal for these materials is toproduce a product that may mimic a soft cloth-like feel or at least getcloser to a soft cloth-like feel than has been previously possible whilestill maintaining acceptable strength and other characteristics.

[0004] Such a soft cloth-like feel is often characterized by, amongother things, one or more of the following: thickness, bulk density,flexibility, texture, softness, density, and durability of the non-wovenmaterials. These materials are suitable for disposable products such as,for example, disposable diapers, disposable tissues and disposablewipes, for example, disposable wet-wipes.

[0005] In the manufacture of products containing pulp fibers, it isoften desirable to enhance physical and/or optical properties of thepulp fibers and/or fibrous nonwoven material by the addition of chemicaladditives onto the pulp fibers and/or fibrous nonwoven material.Typically, chemical additives such as softeners, colorants, brighteners,strength agents, etc. are added to the fiber slurry upstream of theheadbox in a paper making machine during the manufacturing or convertingstages of production to impart certain attributes to the finishedproduct. These chemical additives are usually mixed in a stock chest orstock line where the fiber slurry has a fiber consistency of frombetween about 0.15 to about 5 percent or spraying the wet or dry paperor tissue during production.

[0006] One disadvantage of adding a chemical additive at eachmanufacturing, such as papermaking, machine is that the manufacturer hasto install equipment on each paper machine to accomplish the chemicaladditive addition. This, in many cases, is a costly proposition. Inaddition, the uniformity of the finished product coming off of eachmanufacturing machine may vary depending upon how the chemical additivewas added, variations in chemical additive uniformity andconcentrations, the exact point of chemical additive introduction, waterchemistry differences among the manufacturing machines as well aspersonnel and operational differences of each manufacturing machine.

[0007] Another difficulty associated with wet end chemical additive in asolution addition, such as to a pulp slurry, is that the water solubleor water dispersible chemical additives are suspended in water and arenot completely adsorbed or retained onto the fibers prior to formationof the wet mat. To improve adsorption of wet end chemical additives, thechemical additives are often modified with functional groups to impartan electrical charge when in water. The electrokinetic attractionbetween charged chemical additives and the anionically charged fibersurfaces aids in the deposition and retention of chemical additives ontothe fibers. Nevertheless, the amount of the chemical additive that canbe adsorbed or retained in the manufacturing machine wet end generallyfollows an adsorption curve exhibiting diminishing incrementaladsorption with increasing concentration, similar to that described byLangmuir. As a result, the adsorption of water soluble or waterdispersible chemical additives may be significantly less than 100percent, particularly when trying to achieve high chemical additiveloading levels. The use of water insoluble chemical additives in thewater systems of manufacturing processes is even more problematic andtypically provides even poorer loading levels. Water insoluble chemicaladditives or water nondispersible chemical additives cannot typically beused in such water systems unless in the form of an emulsion.

[0008] Consequently, at any chemical addition level, and particularly athigh addition levels, a fraction of the chemical additive is retained onthe fiber surface. The remaining fraction of the chemical additiveremains dissolved or dispersed in the suspending water phase. Theseunadsorbed or unretained chemical additives can cause a number ofproblems in the manufacturing process. The exact nature of the chemicaladditive will determine the specific problems that may arise, but apartial list of problems that may result from unadsorbed or unretainedchemical additives includes: foam, deposits, contamination of otherfiber streams, poor fiber retention on the machine, compromised chemicallayer purity in multi-layer products, dissolved solids build-up in thewater system, interactions with other process chemicals, felt or fabricplugging, excessive adhesion or release on dryer surfaces, physicalproperty variability in the finished product.

[0009] Therefore, what is lacking and needed in the art is a fibrousnon-woven material or a fibrous non-woven composite material containingpulp fibers wherein water insoluble chemical additives are applied ontothe pulp fibers, providing more consistent water insoluble chemicaladditive additions to the pulp fiber and a reduction or elimination ofunretained water insoluble chemical additives in the process water on apaper machine.

[0010] The present invention minimizes the associated manufacturing andfinished product quality problems that would otherwise occur withconventional wet end chemical addition at the manufacturing machine.

Definitions

[0011] For the purposes of the present application, the following termsshall have the following meanings:

[0012] As used herein the term “chemical additive” refers to a singletreatment compound or to a mixture of treatment compounds. It is alsounderstood that a chemical additive used in the present invention may bean adsorbable chemical additive.

[0013] As used herein the term “non-woven web” means a structure or aweb of material which has been formed without use of weaving processesto produce a structure of individual fibers or threads which areintermeshed, but not in an identifiable, repeating manner. Non-wovenwebs have been, in the past, formed by a variety of conventionalprocesses such as, for example, meltblowing processes, spinbondingprocesses, film aperturing processes and staple fiber carding processes.

[0014] As used herein, the term “meltblown fibers” means fibers formedby extruding a molten thermoplastic material through a plurality offine, usually circular, die capillaries as molten threads or filamentsinto a high velocity gas (e.g. air) stream which attenuates thefilaments of molten thermoplastic material to reduce their diameter,which maybe to microfiber diameter. Thereafter, the meltblown fibers arecarried by the high velocity gas stream and are deposited on acollecting surface to form a web of randomly disbursed meltblown fibers.Such a process is disclosed, for example, in U.S. Pat. No. 3,849,241 toButin.

[0015] As used herein, the term “spunbonded fibers” refers to smalldiameter fibers which are formed by extruding a molten thermoplasticpolymeric material as filaments from a plurality of fine, usuallycircular, capillaries of a spinnerette with the diameter of the extrudedfilaments then being rapidly reduced as by, for example, eductivedrawing or other well-known spun-bonding mechanisms. The production ofspun-bonded non-woven webs is illustrated in patents such as, forexample, in U.S. Pat. No. 4,340,563 to Appel et al., and U.S. Pat. No.3,692,618 to Dorschner et al.

[0016] As used herein, the term “coform” means a non-woven compositematerial of air-formed matrix material comprising thermoplasticpolymeric meltblown fibers such as, for example, microfibers having anaverage fiber diameter of less than about 10 microns, and a multiplicityof individualized absorbent fibers such as, for example, wood pulpfibers disposed throughout the matrix of polymer microfibers andengaging at least some of the microfibers to space the microfibers apartfrom each other. The absorbent fibers are interconnected by and heldcaptive within the matrix of microfibers by mechanical entanglement ofthe microfibers with the absorbent fibers, the mechanical entanglementand interconnection of the microfibers and absorbent fibers aloneforming a coherent integrated fibrous structure. These materials areprepared according to the descriptions in U.S. Pat. No. 4,100,324 toAnderson et al. U.S. Pat. No. 5,508,102 to Georger et al. and U.S. Pat.No. 5,385,775 to Wright.

[0017] As used herein, the term “microfibers” means small diameterfibers having an average diameter not greater than about 100 microns,for example, having an average diameter of from about 0.5 microns toabout 50 microns, or more particularly, microfibers may have an averagediameter of from about 4 microns to about 40 microns.

[0018] As used herein, the term “autogenous bonding” means bondingprovided by fusion and/or self-adhesion of fibers and/or filamentswithout an applied external adhesive or bonding agent. Autogenousbonding may be provided by contact between fibers and/or filaments whileat least a portion of the fibers and/or filaments are semi-molten ortacky. Autogenous bonding may also be provided by blending a tackifyingresin with the thermoplastic polymers used to form the fibers and/orfilaments. Fibers and/or filaments formed from such a blend may beadapted to self-bond with or without the application of pressure and/orheat. Solvents may also be used to cause fusion of fibers and filamentswhich remains after the solvent is removed.

[0019] As used herein, the term “machine direction (MD)” refers to thedirection of travel of the forming surface onto which fibers aredeposited during formation of a non-woven fibrous web.

[0020] As used herein, the term “cross-machine direction (CD)” refers tothe direction which is essentially perpendicular to the machinedirection defined above.

[0021] As used herein, the term “tensile strength” refers to the maximumload or force (i.e., peak load) encountered while elongating the sampleto break. Measurements of peak load are made in the machine andcross-machine directions using wet samples.

[0022] As used herein, the term “wet-wipe” refers to a fibrous sheetwhich, during its manufacture, has a liquid applied thereto so that theliquid may be retained on or within the fibrous sheet until itsutilization by a consumer. The liquid may include a fragrance and/or anemollient and may serve to aid the fibrous sheet in retention ofmaterials which are to be wiped up during its utilization.

[0023] As used herein, the terms “fibrous non-woven material” and“fibrous non-woven composite material” refer to material that may beused as the sheet or substrate for a consumer product, such as awet-wipe or wipe-type product, which has a liquid applied thereto thatmay be retained on or within the fibrous sheet until it is utilized by aconsumer.

[0024] As used herein, the terms “stretch-bonded laminate” or “compositeelastic material” refers to a fabric material having at least one ply ofnon-woven web being elastic and at least one ply of the non-woven webbeing non-elastic, e.g., a gatherable ply. The elastic non-woven webply(s) are joined or bonded in at least two locations to the non-elasticnon-woven web ply(s). Preferably, the bonding is at intermittent bondingpoints or areas while the non-woven web ply (s) are in juxtaposedconfiguration and while the elastic non-woven web ply(s) have atensioning force applied thereto in order to bring the elastic non-wovenweb to a stretched condition. Upon removal of the tensioning force afterjoining of the web plies, an elastic non-woven web ply will attempt torecover to its unstretched condition and will thereby gather thenon-elastic non-woven web ply between the points or areas of joining ofthe two plies. The composite material is elastic in the direction ofstretching of the elastic ply during joining of the plies and may bestretched until the gathers of the non-elastic non-woven web or film plyhave been removed. A stretch-bonded laminate may include more than twoplies. For example, the elastic non-woven web or film may have anon-elastic non-woven web ply joined to both of its sides while it is ina stretched condition so that a three ply non-woven web composite isformed having the structure of gathered non-elastic (non-woven web orfilm)/elastic (non-woven web or film)/gathered non-elastic (non-wovenweb or film). Yet other combinations of elastic and non-elastic pliesmay also be utilized. Such composite elastic materials are disclosed,for example, by U.S. Pat. No. 4,720,415 to Vander Wielen et al., andU.S. Pat. No. 5,385,775 to Wright.

[0025] As used herein “thermal point bonding” involves passing amaterial such as two or more webs of fibers to be bonded between aheated calendar roll and an anvil roll. The calender roll is usually,though not always, patterned in some way so that the entire fabric isnot bonded across its entire surface, and the anvil roll is usually flator crowned. As a result, various patterns for calender rolls have beendeveloped for functional as well as aesthetic reasons. In one embodimentof this invention the bond pattern allows void spaces in the machinedirection to allow a gatherable ply to gather when the web retracts.

[0026] As used herein the term “unretained” refers to any portion of thechemical additive that is not retained by the pulp fiber and thusremains suspended in the process water.

[0027] As used herein the term “web-forming apparatus” includesfourdrinier former, twin wire former, cylinder machine, press former,crescent former, and the like used in the pulp stage known to thoseskilled in the art.

[0028] As used herein the term “water” refers to water or a solutioncontaining water and other treatment additives desired in themanufacturing process or in the finished wet-wipe product.

[0029] As used herein the term “superabsorbent” refers to a waterswellable, substantially insoluble organic or inorganic material capableof absorbing at least 10 times its weight of an aqueous solutioncontaining 0.9 wt % of sodium chloride.

[0030] As used herein the term “palindromic” means a multi-ply laminate,for example a stretch-bonded laminate, which is substantiallysymmetrical. Examples of palindromic laminates could have plyconfigurations of A/B/A, A/B/B/A, A/A/B/B/A/A, A/B/C/B/A, and the like.Examples of non-palindromic ply configurations would include A/B/C,A/B/C/A, A/B/C/D, etc.

[0031] As used herein the term “polymer” generally includes, but is notlimited to, homopolymers, copolymers, such as, for example, block,graft, random and alternating copolymers, terpolymers, etc. and blendsand modifications thereof. Furthermore, unless otherwise specificallylimited, the term “polymer” shall include all possible geometricalconfigurations of the material. These configurations include, but arenot limited to, isotactic, syndiotactic and random symmetries.

[0032] As used herein the term “pulp fiber” is used herein to broadlyinclude fiber used in writing paper, printing paper, wrapping paper,sanitary paper, and industrial papers, newsprint, linerboard, tissue,bath tissue, facial tissue, napkins, wipers, wet-wipes, towels,absorbent pads, intake webs in absorbent articles such as diapers, bedpads, meat and poultry pads, feminine care pads, and the like made inaccordance with any conventional process for the production of suchproducts. With regard to the use of the term “pulp fiber” as used hereinincludes any fibers used in any fibrous web containing cellulosic fibersalone or in combination with other fibers, natural or synthetic. It maybe plied or unplied, layered or unlayered, creped or uncreped, and mayconsist of a single ply or multiple plies. In addition, the fibrous webmay contain reinforcing fibers for integrity and strength.

[0033] As used herein the term “softening agent” refers to any chemicaladditive that may be incorporated into products such as tissue toprovide improved tactile feel and reduce stiffness of the product. Asoftening agent may be selected from the group consisting of quaternaryammonium compounds, quaternized protein compounds, phospholipids,polysiloxane compounds, quaternized, hydrolyzed wheatprotein/dimethicone phosphocopolyol copolymer, organoreactivepolysilxanes, polyhydroxy compounds, and silicone glycols. Thesechemical additives may also act to reduce the stiffness of the productor may act solely to improve the surface characteristics of product,such as by reducing the coefficient of friction between the surface ofthe product and the hand.

[0034] As used herein the term “dye” refers to any chemical that may beincorporated into fibrous non-woven materials or fibrous non-wovencomposite material based products, such as wet-wipes, bathroom tissue,facial tissue, paper towels, and napkins, to impart a color. Dependingon the nature of the chemical, dyes may be classified as acid dyes,basic dyes, direct dyes, cellulose reactive dyes, or pigments. Allclassifications are suitable for use in conjunction with the presentinvention.

[0035] As used herein the term “polyhydroxy compounds” refers tocompounds selected from the group consisting of glycerol, sorbitols,polyglycerols having a weight average molecular weight of from about 150to about 800, polyoxyethylene glycols and polyoxypropylene glycolshaving a weight average molecular weight from typically about 200 toabout 10,000, more typically about 200 to about 4,000.

[0036] As used herein the term “water soluble” refers to solids orliquids that will form a solution in water, and the term “waterdispersible” refers to solids or liquids of colloidal size or largerthat may be dispersed into an aqueous medium. As used herein the term“water insoluble” refers to solids or liquids that will not form asolution in water.

[0037] As used herein the term “bonding agent” refers to any chemicalthat may be incorporated into tissue to increase or enhance the level ofinterfiber or intrafiber bonding in the sheet. The increased bonding maybe either ionic, Hydrogen or covalent in nature. It is understood that abonding agent refers to both dry and wet strength enhancing chemicaladditives.

SUMMARY OF THE INVENTION

[0038] The problem of a fibrous non-woven material lacking desiredcharacteristics or properties, such as softness or cloth-like feel maybe addressed by the application of water insoluble chemical additives topulp fibers at high and/or consistent levels with little or no migrationof the water insoluble chemical additive into the process water orproduct solutions.

[0039] It has now been discovered that water insoluble chemicaladditives can be applied to pulp fibers at high and/or consistent levelswith reduced amounts of unretained water insoluble chemical additivespresent in the manufacturing process water, such as papermaking, afterthe treated pulp fiber has been exposed to a liquid, such as water. Thisis accomplished by treating a fibrous web prior to the finishingoperation at a pulp mill with a water insoluble chemical additive,completing the finishing operation, and using the finished chemicallytreated pulp in the production of a fibrous non-woven material orfibrous non-woven composite material. As used herein, the term “fibrousnon-woven material” is understood to include fibrous non-woven compositematerial(s).

[0040] Hence in one aspect, the invention resides in a method forpreparing chemically treated pulp fibers contained in a fibrousnon-woven material. The method comprises creating a fiber slurrycomprising process water and virgin pulp fibers. The fiber slurry istransported to a web-forming apparatus of a pulp sheet machine andformed into a wet fibrous web. The wet fibrous web is dried to apredetermined consistency thereby forming a dried fibrous web. The driedfibrous web is treated with a water insoluble chemical additive therebyforming a chemically treated dried fibrous web containing chemicallytreated pulp fibers wherein the chemically treated pulp fibers have anincreased or improved level of chemical retention of the water insolublechemical additive and have a level of chemical retention of the waterinsoluble chemical additive is between about 25 to about 100 percentretention of the applied amount of the water insoluble chemical additivewhen the chemically treated pulp fibers are exposed to a liquid, such aswater or product solution. The chemically treated pulp fibers are usedto form the fibrous non-woven material. The level of chemical retentionof the water insoluble chemical additive may range from between about 60to about 100 percent or between about 80 to about 100 percent retentionof the water insoluble chemical additive. The improved level of chemicalretention of the water insoluble chemical additive, measured as thechange in the level of chemical retention of adding by typical wet-endaddition, may range from a lower limit of about 5 percent, about 15percent, about 25 percent, about 35 percent, about 45 percent, about 55percent, about 65 percent, and about 75 percent to a higher limit ofabout 25 percent, about 35 percent, about 45 percent, about 55 percent,about 65 percent, about 75 percent, about 85 percent, about 95 percent,and about 100 percent retention of the water insoluble chemicaladditive. It is understood that the value for the lower limit is lessthan the value for the upper limit. The chemically treated pulp fibermay be then used in a separate process to produce paper products.

[0041] In another aspect, the invention resides in a method for applyinga water insoluble chemical additive to a fibrous non-woven material. Themethod comprises mixing pulp fibers with process water to form a fiberslurry. The fiber slurry is transported to a web-forming apparatus of apulp sheet machine and forming a wet fibrous web. The wet fibrous web isdewatered to a predetermined consistency thereby forming a dewateredfibrous web. A water insoluble chemical additive is applied to thedewatered fibrous web, thereby forming a chemically treated dewateredfibrous web containing chemically treated pulp fibers wherein thechemically treated pulp fibers have an increased or improved level ofchemical retention of the water insoluble chemical additive wherein thelevel of chemical retention of the water insoluble chemical additive isbetween about 25 to about 100 percent of the applied amount of the waterinsoluble chemical additive when the chemically treated pulp fibers areexposed to a liquid. The chemically treated pulp fibers are used to formthe fibrous non-woven material. The level of chemical retention of thewater insoluble chemical additive may range from between about 60 toabout 100 percent or between about 80 to about 100 percent retention ofthe water insoluble chemical additive. The improved level of chemicalretention of the water insoluble chemical additive, measured as thechange in the level of chemical retention of adding by typical wet-endaddition, may range from a lower limit of about 5 percent, about 15percent, about 25 percent, about 35 percent, about 45 percent, about 55percent, about 65 percent, and about 75 percent to a higher limit ofabout 25 percent, about 35 percent, about 45 percent, about 55 percent,about 65 percent, about 75 percent, about 85 percent, about 95 percent,and about 100 percent retention of the water insoluble chemicaladditive. It is understood that the value for the lower limit is lessthan the value for the upper limit.

[0042] According to another embodiment of the present invention is amethod for applying a water insoluble chemical additive to the pulpfibers to be incorporated into a fibrous non-woven material during thepulp processing stage. During the pulp processing stage, upstream of amanufacturing machine, one can obtain chemically treated pulp fiber.Furthermore, the chemically treated pulp fiber can be transported toseveral different manufacturing machines that may be located at varioussites, and the quality of the finished product from each manufacturingmachine will be more consistent. Also, by chemically treating the pulpfiber before the pulp fiber is made available for use on multiplemanufacturing machines or multiple runs on a manufacturing machine, theneed to install equipment at each manufacturing machine for the waterinsoluble chemical additive addition can be eliminated.

[0043] The method of the present invention allows for the production orprocessing of pulp fibers also enables higher and more uniformconcentrations of the water insoluble chemical additive to be retainedby the pulp fibers while at the same time maintaining significantlylower levels of unretained water insoluble chemical additive in thewater phase of a manufacturing machine compared to paper machine wet endchemical additive additions.

[0044] The consistency of the dried fibrous web is from about 65 toabout 100 percent. In other embodiments, the consistency of the driedfibrous web is from about 80 to about 100 percent or from about 85 toabout 95 percent. The consistency of the dewatered fibrous web is fromabout 20 to about 65 percent. In other embodiments, the consistency ofthe dewatered fibrous web is from about 40 to about 65 percent or fromabout 50 to about 65 percent. The consistency of the crumb form is fromabout 20 to about 85 percent. In other embodiments, the consistency ofthe crumb form is from about 30 to about 60 percent or from about 30 toabout 45 percent.

[0045] The present method allows for the production of pulp fibers to beincorporated into a fibrous non-woven material that is useful for makingproducts such as wet-wipe products. One aspect of the present inventionis a uniform supply of chemically treated pulp fiber, replacing the needfor costly and variable chemical treatments at one or more manufacturingmachines. Another aspect of the invention resides in a pulp fiber thathas a higher water insoluble chemical additive loading than couldotherwise be achieved in combination with either no or a relatively lowlevel of unretained water insoluble chemical additive in the processwater on a manufacturing machine. This is because water insolublechemical additive loading via wet end addition is often limited by thelevel of unadsorbed or unretained water insoluble chemical additiveand/or contact time, as well as its associated processing difficultiessuch as foam, deposits, chemical interactions, felt plugging, excessivedryer adhesion or release or a variety of product physical propertycontrol issues caused by the presence of unadsorbed or unretained waterinsoluble chemical additive in the process water on the manufacturingmachines. Another aspect of the invention is the ability to deliver pulpfiber treated with water insoluble chemical additives that would nototherwise be retained when added in the wet end of a manufacturingoperation or product solutions.

[0046] According to one embodiment of the present invention, the methodcomprises adding at least a first chemical additive to pulp fiber. Pulpfibers are mixed with process water thereby forming a fiber slurry. Thefiber slurry is transported to a web-forming apparatus of a pulp sheetmachine. The fiber slurry is dewatered thereby forming a crumb pulp. Awater insoluble chemical additive is applied to the crumb pulp therebyforming a chemically treated crumb pulp containing chemically treatedpulp fibers. The chemically treated pulp fibers have an increased orimproved level of chemical retention of the water insoluble chemicaladditive and have the level of chemical retention of the water insolublechemical additive that is between about 25 to about 100 percentretention of the applied amount of the water insoluble chemical additivewhen the chemically treated pulp fibers are exposed to a liquid. Thechemically treated pulp having the water insoluble chemical additiveretained thereon is used to form a fibrous non-woven material. The levelof chemical retention of the water insoluble chemical additive may rangefrom between about 60 to about 100 percent or between about 80 to about100 percent retention of the water insoluble chemical additive. Theimproved level of chemical retention of the water insoluble chemicaladditive, measured as the change in the level of chemical retention ofadding by typical wet-end addition, may range from a lower limit ofabout 5 percent, about 15 percent, about 25 percent, about 35 percent,about 45 percent, about 55 percent, about 65 percent, and about 75percent to a higher limit of about 25 percent, about 35 percent, about45 percent, about 55 percent, about 65 percent, about 75 percent, about85 percent, about 95 percent, and about 100 percent retention of thewater insoluble chemical additive. It is understood that the value forthe lower limit is less than the value for the upper limit.

[0047] Another aspect of the present invention resides in a method forapplying water insoluble chemical additives to pulp fiber. The methodcomprises creating a fiber slurry comprising process water and pulpfibers. The fiber slurry is transported to a web-forming apparatus of apulp sheet machine and forming a wet fibrous web. The wet fibrous web isdewatered to a predetermined consistency thereby forming a dewateredfibrous web. A first water insoluble chemical additive is applied to thedewatered fibrous web to form a chemically treated dewatered fibrous webof chemically treated pulp fibers. A second water insoluble chemicaladditive is applied to the chemically treated dewatered fibrous webthereby forming a dual chemically treated dewatered fibrous webcontaining dual chemically treated pulp fibers wherein the dualchemically treated pulp fibers have an improved level of chemicalretention of the first water insoluble chemical additive and have alevel of chemical retention of the first water insoluble chemicaladditive that is between about 25 to about 100 percent retention of theapplied amount of the first water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid and whereinthe dual chemically treated pulp fibers have an improved level ofchemical retention of the second water insoluble chemical additive andhave a level of chemical retention of the second water insolublechemical additive that is between about 25 to about 100 percentretention of the applied amount of the second water insoluble chemicaladditive when the dual chemically treated pulp fibers are exposed to aliquid. The chemically treated pulp having the first and second waterinsoluble chemical additives retained thereon is used to form a fibrousnon-woven material. The level of chemical retention of the first and/orsecond water insoluble chemical additive may range from between about 60to about 100 percent or between about 80 to about 100 percent retentionof the applied amount of the first and/or second water insolublechemical additive. The improved level of chemical retention of the firstand/or second water insoluble chemical additive, measured as the changein the level of chemical retention of adding by typical wet-endaddition, may range from a lower limit of about 5 percent, about 15percent, about 25 percent, about 35 percent, about 45 percent, about 55percent, about 65 percent, and about 75 percent to a higher limit ofabout 25 percent, about 35 percent, about 45 percent, about 55 percent,about 65 percent, about 75 percent, about 85 percent, about 95 percent,and about 100 percent retention of the first and/or second waterinsoluble chemical additive, respectively. It is understood that thevalue for the lower limit is less than the value for the upper limit.

[0048] Another aspect of the present invention resides in a method forapplying water insoluble chemical additives to pulp fiber. The methodcomprises mixing pulp fibers with process water to form a fiber slurry.The fiber slurry is transported to a web-forming apparatus of a pulpsheet machine and forming a wet fibrous web. The wet fibrous web isdewatered to a predetermined consistency thereby forming a dewateredfibrous web. The dewatered fibrous web is dried to a predeterminedconsistency thereby forming a dried fibrous web. A first water insolublechemical additive is applied to the dried fibrous web and applying asecond water insoluble chemical additive to the dried fibrous web,thereby forming a dual chemically treated dewatered fibrous webcontaining dual chemically treated pulp fibers wherein the dualchemically treated pulp fibers have an improved level of chemicalretention of the first water insoluble chemical additive and have alevel of chemical retention of the first water insoluble chemicaladditive is between about 25 to about 100 percent retention of theapplied amount of the first water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid and whereinthe dual chemically treated pulp fibers have an improved level ofchemical retention of the second water insoluble chemical additive andhave a level of chemical retention of the second water insolublechemical additive is between about 25 to about 100 percent retention ofthe applied second water insoluble chemical additive when the dualchemically treated pulp fibers are exposed to a liquid. The chemicallytreated pulp having the first and second water insoluble chemicaladditives retained thereon is used to form a fibrous non-woven material.The level of chemical retention of the first and/or second waterinsoluble chemical additive may range from between about 60 to about 100percent or between about 80 to about 100 percent retention of theapplied amount of the first and/or second water insoluble chemicaladditive. The improved level of chemical retention of the first and/orsecond water insoluble chemical additive, measured as the change in thelevel of chemical retention of adding by typical wet-end addition, mayrange from a lower limit of about 5 percent, about 15 percent, about 25percent, about 35 percent, about 45 percent, about 55 percent, about 65percent, and about 75 percent to a higher limit of about 25 percent,about 35 percent, about 45 percent, about 55 percent, about 65 percent,about 75 percent, about 85 percent, about 95 percent, and about 100percent retention of the first and/or second water insoluble chemicaladditive, respectively. It is understood that the value for the lowerlimit is less than the value for the upper limit. A finished producthaving enhanced qualities due to the retention of the chemical additiveby the pulp fibers may be produced.

[0049] Another aspect of the present invention resides in a method forapplying water insoluble chemical additives to pulp fiber. The methodcomprises mixing pulp fibers with process water to form a fiber slurry.The fiber slurry is transported to a web-forming apparatus of a pulpsheet machine and forming a wet fibrous web. The wet fibrous web isdewatered to a predetermined consistency thereby forming a dewateredfibrous web. Applying a first water insoluble chemical additive to thedewatered fibrous web to the dewatered fibrous web thereby forming achemically treated dewatered fibrous web. The chemically treateddewatered fibrous web is dried to a predetermined consistency therebyforming a chemically treated dried fibrous web. A second water insolublechemical additive is applied to the chemically treated dried fibrousweb, thereby forming a dual chemically treated dried fibrous webcontaining dual chemically treated pulp fibers wherein the dualchemically treated pulp fibers have an improved level of chemicalretention of the first water insoluble chemical additive and have alevel of chemical retention of the first water insoluble chemicaladditive that is between about 25 to about 100 percent retention of theapplied amount of the first water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid and whereinthe dual chemically treated pulp fibers have an improved level ofchemical retention of the second water insoluble chemical additive andhave a level of chemical retention of the second water insolublechemical additive that is between about 25 to about 100 percentretention of the applied amount of the second water insoluble chemicaladditive when the dual chemically treated pulp fibers are exposed to aliquid. The chemically treated pulp having the first and second waterinsoluble chemical additives retained thereon is used to form a fibrousnon-woven material. The level of chemical retention of the first and/orsecond water insoluble chemical additive may range from between about 60to about 100 percent or between about 80 to about 100 percent retentionof the applied amount of the first and/or second water insolublechemical additive. The improved level of chemical retention of the firstand/or second water insoluble chemical additive, measured as the changein the level of chemical retention of adding by typical wet-endaddition, may range from a lower limit of about 5 percent, about 15percent, about 25 percent, about 35 percent, about 45 percent, about 55percent, about 65 percent, and about 75 percent to a higher limit ofabout 25 percent, about 35 percent, about 45 percent, about 55 percent,about 65 percent, about 75 percent, about 85 percent, about 95 percent,and about 100 percent retention of the first and/or second waterinsoluble chemical additive, respectively. It is understood that thevalue for the lower limit is less than the value for the upper limit. Afinished product having enhanced qualities due to the retention of thechemical additive by the pulp fibers may be produced.

[0050] The present invention is particularly useful for adding waterinsoluble chemical additives such as softening agents to the pulpfibers, allowing for the less problematic and lower cost production offinished products having enhanced qualities provided by the retainedwater insoluble chemical additives by the pulp fibers.

[0051] Hence, another aspect of the present invention resides in fibrousnon-woven materials and products made therefrom formed from pulp fibersthat have been chemically treated to minimize the amount of residual,unretained water insoluble chemical additives in the process water on amanufacturing machine or in the product solutions.

[0052] The method for applying water insoluble chemical additives to thepulp fibers may be used in a wide variety of pulp finishing processing,including dry lap pulp, wet lap pulp, crumb pulp, and flash dried pulpoperations. By way of illustration, various pulp finishing processes(also referred to as pulp processing) are disclosed in Pulp and PaperManufacture: The Pulping of Wood, 2^(nd) Ed., Volume 1, Chapter 12.Ronald G. MacDonald, editor, which is incorporated by reference. Variousmethods may be used to apply the water insoluble chemical additives inthe present invention, including, but not limited to: spraying, dipping,coating, foaming, printing, size pressing, or any other method known inthe art.

[0053] In addition, in situations where more than one water insolublechemical additive is to be employed, the water insoluble chemicaladditives may be added to the fibrous web in sequence to reduceinteractions between the water insoluble chemical additives.

[0054] Many pulp fiber types may be used for the present inventionincluding hardwood or softwoods, straw, flax, milkweed seed flossfibers, abaca, hemp, kenaf, bagasse, cotton, reed, and the like. Allknown papermaking fibers may be used, including bleached and unbleachedfibers, fibers of natural origin (including wood fiber and othercellulose fibers, cellulose derivatives, and chemically stiffened orcrosslinked fibers), some component portion of synthetic fiber(synthetic papermaking fibers include certain forms of fibers made frompolypropylene, acrylic, aramids, acetates, and the like), virgin andrecovered or recycled fibers, hardwood and softwood, and fibers thathave been mechanically pulped (e.g., groundwood), chemically pulped(including but not limited to the kraft and sulfite pulp processings),thermomechanically pulped, chemithermomechanically pulped, and the like.Mixtures of any subset of the above mentioned or related fiber classesmay be used. The pulp fibers can be prepared in a multiplicity of waysknown to be advantageous in the art. Useful methods of preparing fibersinclude dispersion to impart curl and improved drying properties, suchas disclosed in U.S. Pat. No. 5,348,620 issued Sep. 20, 1994 and U.S.Pat. No. 5,501,768 issued Mar. 26, 1996, both to M. A. Hermans et al.and U.S. Pat. No. 5,656,132 issued Aug. 12, 1997 to Farrington, Jr. etal.

[0055] According to the present invention, the chemical treatment of thepulp fibers may occur prior to, during, or after the drying phase of thepulp processing. The generally accepted methods of drying include flashdrying, can drying, flack drying, through air drying, Infra-red drying,fluidized bed, or any method of drying known in the art. The presentinvention may also be applied to wet lap pulp processes without the useof dryers.

[0056] Numerous features and advantages of the present invention willappear from the following description. In the description, reference ismade to the accompanying drawings which illustrate preferred embodimentsof the invention. Such embodiments do not represent the full scope ofthe invention. Reference should therefore be made to the claims hereinfor interpreting the full scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0057]FIG. 1 depicts a schematic process flow diagram of a methodaccording to the present invention for treating pulp fibers with asingle water insoluble chemical additive.

[0058]FIG. 2 depicts a schematic process flow diagram of a methodaccording to the present invention for treating pulp fibers withmultiple water insoluble chemical additives.

[0059]FIG. 3 depicts a schematic process flow diagram of a method ofmaking a fibrous non-woven material.

[0060]FIG. 4 depicts a fluidized bed apparatus for applying waterinsoluble chemical additives to pulp fibers.

[0061]FIG. 5 depicts a fluidized bed apparatus for applying waterinsoluble chemical additives to pulp fibers.

DETAILED DESCRIPTION

[0062] The present invention provides a fibrous non-woven material orfibrous non-woven composite material adapted to provide improvedsoftness and cloth-like feel in a finished product, such as a wet-wipe.The feel of a wet-wipe is often characterized by one or more of thefollowing attributes of the fibrous non-woven materials that comprisethem: thickness, bulk density, flexibility, texture, softness, anddurability. In preparing a wet-wipe having a soft cloth-like feel, it isimportant to balance the properties of the non-woven material ornon-woven composite material, e.g., cup crush, density, and tensilestrength. However, this is a difficult task because these properties maybe interdependent, i.e., changing one property may affect anotherproperty (and the overall feel of the wet-wipe). Typically, when thebasis weight is decreased, the cup-crush is decreased, and tensilestrength is decreased. When the basis weight is increased then thereverse changes occur. Thus, when a property is varied, to enhance thesoftness, careful attention should be paid to the results obtained toavoid a resultant product having less desirable overall properties. Itis understood that the fibrous non-woven material or fibrous non-wovencomposite material may be layered and that discussions regarding a plyor plies may also be applied to a layer or layers.

[0063] The wet-wipes of the present invention include at least one plyof fibrous non-woven material or fibrous non-woven composite material.The preferred CD tensile strength of the fibrous non-woven material orthe fibrous non-woven composite material of the wet-wipe is of greaterthan about 0.70 lbs. A more preferred CD tensile strength is of greaterthan about 0.75 lbs. A slightly more preferred CD tensile strength is ofgreater than about 0.80 lbs. A yet more preferred CD tensile strength isof greater than about 0.85 lbs. A much more preferred CD tensilestrength is of greater than about 0.90 lbs. A very much more preferredCD tensile strength is of greater than about 0.95 lbs. The mostpreferred CD tensile strength is of greater than about 1.0 lbs.

[0064] The basis weight (in grams per square meter, g/m² or gsm) of thefibrous non-woven material of the wet-wipe is calculated by dividing thedry weight by the area (in square meters). The density of the fibrousnon-woven material or fibrous non-woven composite material of thewet-wipe, as used herein, is a “wet density” and is calculated as thebasis weight (in grams per square meter, g/m² or gsm) divided by thethickness of the wet-wipe after wetting with the solution.

[0065] The wet-wipes of the present invention comprise a fibrousnon-woven material or a fibrous non-woven composite material and aliquid. The liquid may be any solution which may be absorbed into thewet-wipe composite elastic material and may include any suitablecomponents which provide the desired wiping properties. For example, thecomponents may include water, emollients, surfactants, fragrances,preservatives, chelating agents, pH buffers or combinations thereof asare well known to those skilled in the art. The liquid may also containlotions and/or medicaments.

[0066] The amount of liquid contained within each wet-wipe may varydepending upon the type of material being used to provide the wet-wipe,the type of liquid being used, the type of container being used to storethe wet-wipes, and the desired end use of the wet-wipe. Generally, eachwet-wipe may contain from about 150 to about 600 weight percent andpreferably from about 250 to about 450 weight percent liquid based onthe dry weight of the wipe for improved wiping. In a more preferredaspect, the amount of liquid contained within the wet-wipe is from about300 to about 400 weight percent and desirably about 330 weight percentbased on the dry weight of the wet-wipe. If the amount of liquid is lessthan the above-identified ranges, the wet-wipe may be too dry and maynot adequately perform. If the amount of liquid is greater than theabove-identified ranges, the wet-wipe may be oversaturated and soggy andthe liquid may pool in the bottom of the container.

[0067] Each wet-wipe is generally rectangular in shape and may have anysuitable unfolded width and length. For example, the wet-wipe may havean unfolded length of from about 2.0 to about 80.0 centimeters anddesirably from about 10.0 to about 25.0 centimeters and an unfoldedwidth of from about 2.0 to about 80.0 centimeters and desirably fromabout 10.0 to about 25.0 centimeters. Preferably, each individualwet-wipe is arranged in a folded configuration and stacked one on top ofthe other to provide a stack of wet-wipes or interfolded in aconfiguration suitable for pop-up dispensing. Such folded configurationsare well known to those skilled in the art and include c-folded,z-folded, quarter-folded configurations and the like. The stack offolded wet-wipes may be placed in the interior of a container, such as aplastic tub, to provide a package of wet-wipes for eventual sale to theconsumer. Alternatively, the wet-wipes may include a continuous strip ofmaterial which has perforations between each wipe and which may bearranged in a stack or wound into a roll for dispensing.

[0068] The fibrous non-woven material or fibrous non-woven compositematerial of the wet-wipes of the present invention may include at leasttwo plies of material having different physical properties. Thedifferent physical properties which a ply may be configured to provideby selecting the appropriate materials include softness, resiliency,strength, flexibility, integrity, toughness, absorbency, liquidretention, thickness, tear resistance, surface texture, drapability,hand, wetability, wicking ability and the like and combinations thereof.Preferably, the fibrous non-woven materials and/or fibrous non-wovencomposite materials used in a plied wet-wipe are configured to providesoftness and flexibility while maintaining adequate strength, integrityand resiliency, particularly when wetted. For example, the wet-wipes mayinclude at least one ply of fibrous non-woven material or fibrousnon-woven composite material which is configured to provide strength andresilience to the wet-wipe and at least one other ply of a fibrousnon-woven material or fibrous non-woven composite material which isconfigured to provide a soft, gentle wiping surface to the wet-wipe.Preferably, the wet-wipes include a soft ply on each side of a strongand resilient ply such that both exposed surfaces of the wipe provide asoft, gentle surface for contact with the skin.

[0069] The fibrous non-woven material or fibrous non-woven compositematerial may be formed by the microfibers and wood pulp fibers withoutany adhesive, molecular or hydrogen bonds between the two differenttypes of fibers. The absorbent fibers are preferably distributeduniformly throughout the matrix of microfibers to provide a homogeneousmaterial. The material is formed by initially forming a primary airstream containing the melt blown microfibers, forming a secondary airstream containing the wood pulp fibers, merging the primary andsecondary streams under turbulent conditions to form an integrated airstream containing a thorough mixture of the microfibers and wood pulpfibers, and then directing the integrated air stream onto a formingsurface to air form the fabric-like material. The microfibers are in asoft nascent condition at an elevated temperature when they areturbulently mixed with the wood pulp fibers in air.

[0070] In one embodiment of the present invention, the ply(s) of fibrousnon-woven material or fibrous non-woven composite material may have fromabout 20 to about 50 wt. % of the polymer fibers and from about 80 toabout 50 wt. % of the pulp fibers. A more specific ratio of the polymerfibers to the pulp fibers may be from about 25 to about 40 wt. % of thepolymer fibers and from about 75 to about 60 wt. % of the pulp fibers. Amore specific ratio of the polymer fibers to the pulp fibers may be fromabout 30 to about 40 wt. % of the polymer fibers and from about 70 toabout 60 wt. % of the pulp fibers. The most specific ratio of thepolymer fibers to the pulp fibers may be about 35 wt. % of the polymerfibers and about 65 wt. % of the pulp fibers.

[0071] Non-limiting examples of the polymers suitable for practicing theinvention are polyolefin materials such as, for example, polyethylene,polypropylene and polybutylene, including ethylene copolymers, propylenecopolymers and butylene copolymers thereof. A particularly usefulpolypropylene is Basell PF-105. Additional polymers are disclosed inU.S. Pat. No. 5,385,775.

[0072] Pulp fibers of diverse natural origin are applicable in thepresent invention. Digested cellulose fibers from softwood (derived fromconiferous trees), hardwood (derived from deciduous trees) or cottonlinters may be utilized. Pulp fibers from Esparto grass, bagasse, kemp,flax, and other lignaceous and cellulose fiber sources may also beutilized as raw material in the present invention. For reasons of cost,ease of manufacture and disposability, preferred fibers are thosederived from wood pulp (i.e., cellulose fibers). A commercial example ofsuch a wood pulp material is available from Weyerhaeuser as CF-405.Generally wood pulp fibers may be utilized. Applicable wood pulpsinclude chemical pulps, such as Kraft (i.e., sulfate) and sulfite pulps,as well as mechanical pulps including, for example, groundwood,thermomechanical pulp (i.e., TMP) and chemithermomechanical pulp (i.e.,CTMP). Completely bleached, partially bleached and unbleached fibers areuseful herein. It may frequently be desired to utilize bleached pulp forits superior brightness and consumer appeal.

[0073] Also useful in the present invention are fibers derived fromrecycled paper, which may contain any or all of the above categories aswell as other non-fibrous materials such as fillers and adhesives usedto facilitate the original paper making process.

[0074] The ply(s) of fibrous non-woven material or fibrous non-wovencomposite material may be non-woven materials such as, for example,spunbonded webs, meltblown webs, air laid ply webs, bonded carded webs,hydroentangled webs, wet-formed webs or any combination thereof. In oneembodiment of the present invention, one or more plies of a multi-plyfibrous non-woven material and/or fibrous non-woven composite materialhaving, for example, at least one ply of spunbonded web joined to atleast one ply of meltblown web, bonded carded web or other suitablematerial.

[0075] One or both of the plies of a multi-ply product may be acomposite material made of a mixture of two or more different fibers ora mixture of fibers and particulates. Such mixtures may be formed byadding fibers and/or particulates to the gas stream in which meltblownfibers are carried so that an intimate entangled commingling ofmeltblown fibers and other materials, e.g., wood pulp, staple fibers andparticulates such as, for example, hydrocolloid (hydrogel) particulatescommonly referred to as superabsorbent materials, occurs prior tocollection of the meltblown fibers upon a collecting device to form acoherent web of randomly dispersed meltblown fibers and other materialssuch as disclosed in U.S. Pat. No. 4,100,324, to Anderson et al.

[0076] A suitable material for practicing the present invention is afibrous non-woven composite material commonly referred to as “coform.”Coform is an air-formed matrix material of thermoplastic polymericmeltblown fibers such as, for example, microfibers having an averagefiber diameter of less than about 10 microns, and a multiplicity ofindividualized absorbent pulp fibers such as, for example, wood pulpfibers disposed throughout the matrix of polymer microfibers andengaging at least some of the microfibers to space the microfibers apartfrom each other. The absorbent pulp fibers are interconnected by andheld captive within the matrix of microfibers by mechanical entanglementof the microfibers with the absorbent pulp fibers, the mechanicalentanglement and interconnection of the microfibers and absorbent pulpfibers alone forming a coherent integrated fibrous non-woven structure.

[0077] The coherent integrated fibrous structure may be formed by themicrofibers and absorbent pulp fibers without any adhesive, molecular orhydrogen bonds between the two different types of fibers. The absorbentpulp fibers are typcially distributed uniformly throughout the matrix ofmicrofibers to provide a homogeneous material. The fibrous non-wovenmaterial is formed by initially forming a primary air stream containingthe melt blown microfibers, forming a secondary air stream containingthe wood pulp fibers, merging the primary and secondary streams underturbulent conditions to form an integrated air stream containing athorough mixture of the microfibers and wood pulp fibers, and thendirecting the integrated air stream onto a forming surface to air formthe fabric-like material. The microfibers are in a soft nascentcondition at an elevated temperature when they are turbulently mixedwith the wood pulp fibers in air.

[0078] In one embodiment of the present invention, the plies of fibrousnon-woven material or fibrous non-woven composite material are coformplies having from about 20 to about 50 wt. % of the polymer fibers andfrom about 80 to about 50 wt. % of the pulp fibers. A more specificratio of the polymer fibers to the pulp fibers may be from about 25 toabout 40 wt. % of the polymer fibers and from about 75 to about 60 wt. %of the pulp fibers. A more specific ratio of the polymer fibers to thepulp fibers may be from about 30 to about 40 wt. % of the polymer fibersand from about 70 to about 60 wt. % of the pulp fibers. The mostspecifically the ratio of the polymer fibers to the pulp fibers is about35 wt. % of the polymer fibers and about 65 wt. % of the pulp fibers.

[0079] One of the plies of fibrous non-woven material may be made ofpulp fibers, including wood pulp fibers, to form a material such as, forexample, a tissue ply. Additionally, the plies of fibrous non-wovenmaterial or fibrous non-woven composite material may be plies ofhydraulically entangled fibers such as, for example, hydraulicallyentangled mixtures of wood pulp and staple fibers such as disclosed inU.S. Pat. No. 4,781,966, to Taylor.

[0080] The plies of fibrous non-woven material or fibrous non-wovencomposite material may be joined together or to other plies of materialin at least two places by any suitable means such as, for example,thermal bonding or ultrasonic welding which softens at least portions ofat least one of the materials. The joining may be produced by applyingheat and/or pressure to the materials of the plies by heating theseportions to at least the softening temperature of the material with thelowest softening temperature to form a reasonably strong and permanentbond between the re-solidified softened portions of the materials of theplies.

[0081] As may be appreciated, the bonding between the plies may be apoint bonding. Various bonding patterns may be used, depending upon thedesired tactile properties of the final composite laminate of the plies.The bonding points are preferably evenly distributed over the bondingarea of the plies.

[0082] With regard to thermal bonding, one skilled in the art willappreciate that the temperature to which the materials comprising theplies, or at least the bond sites thereof, are heated for heat-bondingwill depend not only on the temperature of the heated roller(s) or otherheat sources but on the residence time of the materials on the heatedsurfaces, the compositions of the materials comprising the plies, thebasis weights of the materials of the plies and the specific heats andthermal conductivities of the materials of the plies. Typically, thebonding may be conducted at a temperature of from about 40° to about 80°C. Specifically, the bonding may be conducted at a temperature of fromabout 55° to about 75° C. More specifically, the bonding may beconducted at a temperature of from about 60° to about 70° C. The typicalpressure range, on the rollers, may be from about 18 to about 56.8 Kgper linear cm (KLC) The specific pressure range, on the rollers, may befrom about 18 to about 24 Kg per linear cm (KLC). However, for a givencombination of materials of the plies, and in view of the hereincontained disclosure the processing conditions necessary to achievesatisfactory bonding may be readily determined by one of skill in theart.

[0083] The present invention will now be described in greater detailwith reference to the Figures. A variety of conventional pulpingapparatuses and operations can be used with respect to the pulpingphase, pulp processing, and drying of pulp fiber. It is understood thatthe pulp fibers could be virgin pulp fiber or recycled pulp fiber.Nevertheless, particular conventional components are illustrated forpurposes of providing the context in which the various embodiments ofthe present invention can be used. Improved retention of chemicaladditives by the pulp fibers may be obtained by treating the pulp fibersaccording to the present invention rather than treating the pulp fibersin wet end additions at manufacturing machines. In addition, the presentinvention allows for quick pulp fiber grade changes at the manufacturingmills.

[0084]FIG. 1 depicts pulp processing preparation equipment used to applywater insoluble chemical additives to pulp fibers according to oneembodiment of the present invention. A fiber slurry 10 is prepared andthereafter transferred through suitable conduits (not shown) to theheadbox 28 where the fiber slurry 10 is injected or deposited into afourdrinier section 30 thereby forming a wet fibrous web 32. The wetfibrous web 32 may be subjected to mechanical pressure to remove processwater. It is understood that the process water may contain processchemicals used in treating the fiber slurry 10 prior to a web formationstep. In the illustrated embodiment, the fourdrinier section 30 precedesa press section 44, although alternative dewatering devices such as anip thickening device, or the like may be used in a pulp sheet machine.The fiber slurry 10 is deposited onto a foraminous fabric 46 such thatthe fourdrinier section filtrate 48 is removed from the wet fibrous web32. The fourdrinier section filtrate 48 comprises a portion of theprocess water. The press section 44 or other dewatering device known inthe art suitably increases the fiber consistency of the wet fibrous web32 to about 30 percent or greater, and particularly about 40 percent orgreater thereby creating a dewatered web 33. The process water removedas fourdrinier section filtrate 48 during the web forming step may beused as dilution water for dilution stages in the pulp processing ordiscarded.

[0085] The dewatered fibrous web 33 may be further dewatered inadditional press sections or other dewatering devices known in the art.The suitably dewatered fibrous web 33 may be transferred to a dryersection 34 where evaporative drying is carried out on the dewateredfibrous web 33 to an airdry consistency, thereby forming a dried fibrousweb 36. The dried fibrous web 36 is thereafter wound on a reel 37 orslit, cut into sheets, and baled via a baler (not shown) for delivery tomanufacturing machines 38 (shown in FIG. 3).

[0086] A water insoluble chemical additive 24 may be added or applied tothe dewatered fibrous web 33 or the dried fibrous web 36 at a variety ofaddition points 35 a, 35 b, 35 c, and 35 d as shown in FIG. 1. It isunderstood that while only four addition points 35 a, 35 b, 35 c, and 35d are shown in FIG. 1, the application of the water insoluble chemicaladditive 24 may occur at any point between the point of initialdewatering of the wet fibrous web 32 to the point the dried fibrous web36 is wound on the reel 37 or baled for transport to the manufacturingmachines 38. The addition point 35 a shows the addition of the waterinsoluble chemical additive 24 within press section 44. The additionpoint 35 b shows the addition of the water insoluble chemical additive24 between the press section 44 and the dryer section 34. The additionpoint 35 c shows the addition of the water insoluble chemical additivein the dryer section 34. The addition point 35 d shows the addition ofthe water insoluble chemical additive 24 between the dryer section 34and the reel 37 or baler (not shown).

[0087] The amount of water insoluble chemical additive retained by thechemically treated pulp fibers is about 0.1 kilogram per metric ton orgreater. In particularly desirable embodiments, the amount of retainedwater insoluble chemical additive is about 0.5 kg/metric ton or greater,particularly about 1 kg/metric ton or greater, and more particularlyabout 2 kg/metric ton or greater. Once the chemically treated pulpfibers are exposed to a liquid, the amount of unretained water insolublechemical additive in the process water phase or product solution isbetween 0 and about 50 percent, particularly between 0 and about 30percent, and more particularly between 0 and about 10 percent, of theamount of water insoluble chemical additive retained by the chemicallytreated pulp fibers.

[0088] Chemistries suitable for use in the present invention includethose not soluble in water. Particularly useful are those waterinsoluble chemistries that provide a product enhancement benefit whenincorporated into a fibrous non-woven material and products madetherefrom. Even more useful are those water insoluble chemistries thatwill not extract with water after having been adsorbed onto cellulosicfiber surfaces. Chemical classifications suitable for use in theinvention include, but are not limited to, mineral oil, petrolatum,olefins, alcohols, fatty alcohols, ethoxylated fatty alcohols, esters,high molecular weight carboxylic and polycarboxylic acids and theirsalts, polydimethylsiloxane and modified polydimethylsiloxane. Modifiedpolydimethylsiloxanes can include amino-functionalpolydimethylsiloxanes, alkylene oxide-modified polydimethylsiloxane,organomodified polysiloxanes, mixtures of cyclic and non-cyclic modifiedpolydimethylsiloxanes and the like. It should be recognized that waterinsoluble chemical additives can be applied as dispersions or emulsionsand still fall within the scope of the present invention.

[0089] A list of water insoluble chemical additives that can be used inconjunction with the present invention include: dry strength agents, wetstrength agents, softening agents, debonding agents, adsorbency agents,sizing agents, dyes, optical brighteners, chemical tracers, opacifiers,dryer adhesive chemicals, and the like. Additional water insolublechemical additives may include: pigments, emollients, humectants,viricides, bactericides, buffers, waxes, fluoropolymers, odor controlmaterials and deodorants, zeolites, perfumes, vegetable and mineraloils, polysiloxane compounds, surfactants, moisturizers, UV blockers,antibiotic agents, lotions, fungicides, preservatives, aloe-veraextract, vitamin E, or the like.

[0090] Polysiloxanes encompass a very broad class of compounds. They arecharacterized in having a backbone structure:

[0091] where R′ and R″ can be a broad range of organo and non-organogroups including mixtures of such groups and where n is an integer ≧2.These polysiloxanes may be linear, branched or cyclic. They include awide variety of polysiloxane copolymers containing various compositionsof functional groups, hence, R′ and R″ actually may represent manydifferent types of groups within the same polymer molecule. The organoor non-organo groups may be capable of reacting with cellulose tocovalently, ionically or hydrogen bond the polysiloxane to thecellulose. These functional groups may also be capable of reacting withthemselves to form crosslinked matrixes with the cellulose. The scope ofthe invention should not be construed as limited by a particularpolysiloxane structure so long as that polysiloxane structure deliversthe aforementioned product or process benefits.

[0092] While not wishing to be bound by theory, the softness benefitsthat polysiloxanes deliver to cellulose containing products is believedto be, in part, related to the molecular weight of the polysiloxane.Viscosity is often used as an indication of molecular weight of thepolysiloxane as exact number or weight average molecular weights areoften difficult to determine. The viscosity of the polysiloxanes of thepresent invention is greater than about 25 centipoise, more typicallygreater than 50 centipoise and most typcially greater than 100centipoise. Viscosity as referred to herein refers to the viscosity ofthe neat polysiloxane itself and not to the viscosity of an emulsion ifso delivered. It should also be understood that the polysiloxanes of thecurrent invention may be delivered as solutions containing diluents.Such diluents may lower the viscosity of the solution below thelimitations set above, however, the efficacious part of the polysiloxaneshould conform to the viscosity ranges given above. Examples of suchdiluents include but is not limited to oligomeric and cyclo-oligomericpolysiloxanes such as octamethylcyclotetrasiloxane,octamethyltrisiloxane, decamethylcyclopentasiloxane,decamethyltetrasiloxane and the like including mixtures of saidcompounds.

[0093] A specific class of polysiloxanes suitable for the invention hasthe general formula:

[0094] Wherein the R¹-R⁸ moieties can be independently anyorganofunctional group including C₁ or higher alkyl groups, ethers,polyethers, polyesters, amines, imines, amides, or other functionalgroups including the alkyl and alkenyl analogues of such groups and y isan integer >1. Preferably the R¹-R⁸ moieties are independently any C₁orhigher alkyl group including mixtures of said alkyl groups. Exemplaryfluids are the DC-200 fluid series, manufactured and sold by DowCorning, Inc.

[0095] Another exemplary class of functionalized polysiloxanes suitablefor the present invention is the polyether polysiloxanes. Suchpolysiloxanes are widely taught in the art and are usually incorporatedwholly or in part with other functional polysiloxanes as a means ofimproving hydrophilicity of the silicone treated product. Suchpolysiloxanes will generally have the following structure:

[0096] Wherein, x and z are integers >0. y is an integer ≧0. The moleratio of x to (x+y+z) can be from about 0.05 percent to about 95percent. The ratio of y to (x+y+z) can be from about 0 percent to about25%. The R⁰-R⁹ moieties can be independently any organofunctional groupincluding C₁ or higher alkyl groups, ethers, polyethers, polyesters,amines, imines, amides, or other functional groups including the alkyland alkenyl analogues of such groups. The R¹⁰ moiety is an aminofunctional moiety including but not limited to primary amine, secondaryamine, tertiary amines, quaternary amines, unsubstituted amides andmixtures thereof. An exemplary R¹⁰ moiety contains one amine group perconstituent or two or more amine groups per substituent, separated by alinear or branched alkyl chain of C¹ or greater. R¹¹ is a polyetherfunctional group having the generic formula:—R¹²—(R¹³—O)_(a)—(R¹⁴O)_(b)—R¹⁵, wherein R¹², R¹³, and R¹⁴ areindependently C₁₋₄ alkyl groups, linear or branched; R¹⁵ can be H or aC₁₋₃₀ alkyl group; and, “a” and “b” are integers of from about 1 toabout 100, more specifically from about 5 to about 30. Exemplary fluidsare the Wetsoft CTW family manufactured and sold by Wacker, Inc. Otherexemplary fluids can be found in U.S. Pat. No. 6,432,270 issued to Liu,et. al. and incorporated by reference herein.

[0097] Most typically, the polysiloxane is chosen from the group of socalled “amino functional” functional polysiloxanes of the generalformula:

[0098] Wherein, x and y are integers >0. The mole ratio of x to (x+y)can be from about 0.005 percent to about 25 percent. The R¹-R⁹ moietiescan be independently any organofunctional group including C₁ or higheralkyl groups, ethers, polyethers, polyesters, amines, imines, amides, orother functional groups including the alkyl and alkenyl analogues ofsuch groups. The R₁₀ moiety is an amino functional moiety including butnot limited to primary amine, secondary amine, tertiary amines,quaternary amines, unsubstituted amides and mixtures thereof. Anexemplary R¹⁰ moiety contains one amine group per constituent or two ormore amine groups per substituent, separated by a linear or branchedalkyl chain of C¹ or greater. An exemplary material includes but is notlimited to 2-8220 fluid manufactured and sold by Dow Corning.

[0099] It should also be recognized that often it is advantageous to usea blend of various functional polysiloxanes. For example, aminofunctional polysiloxanes may be blended with polyether functionalpolysiloxanes and this blend applied to the product. The polyetherfunctional polysiloxane helps mitigate any undesirable hydrophobicitywithin the product. It should be understood that such blends fall withinthe scope of the present invention.

[0100] At the manufacturing machines 38, one example of such machines 38is shown in FIG. 3, a primary gas stream 66 containing polymericmicrofibers, formed by any known method, such as meltblown techniques.The molten polymeric material is extruded through a diehead 68 byconverging flows of high velocity heated gas (usually air) supplied fromnozzles 70 and 72. The primary gas stream 66 is merged with a secondarygas stream 74 containing individualized chemically treated pulp fibershaving the chemical additive 24 so as to integrate the two differentfibrous materials into a single integrated stream 76 in a single step.The manufacturing machine 38 typically includes a conventional pickerroll 78 having teeth for divellicating pulp sheets 80 into individualchemically treated pulp fibers having the chemical additive 24. Thechemically treated pulp sheets 80 having the chemical additive 24 arefed radially by means of rolls 82. The individualized chemically treatedpulp fibers having the chemical additive 24 are conveyed downwardlytoward the primary air stream 66 through a forming nozzle or duct 84. Ahousing 86 encloses the picker roll 78 and provides a passage 88 betweenthe housing 86 and the surface of the picker roll 78. The secondary gasstream 74 supplied through duct 90 passes through the passage 88 whilecarrying the individualized chemically treated pulp fibers having thechemical additive 24 through the forming nozzle 84. To convert thefibrous blend in the integrated stream 76 into an integral fibrousnon-woven material or fibrous non-woven composite material 92, theintegrated stream 76 passes through a nip of a pair of vacuum rolls 94and 96 having foraminous surfaces that rotate continuously over a pairof fixed vacuum nozzles 98 and 100. As the integrated stream 76 ispulled into the vacuum nozzles 98 and 100, the carrying gas is removedwhile the fibrous blend is supported and slightly compressed by theopposed surfaces of the two rolls 94 and 96. The integral fibrousnon-woven material or fibrous non-woven composite material 92 removedfrom the vacuum roll nip and conveyed to a wind-up roll 102. Theintegral fibrous non-woven material or fibrous non-woven compositematerial 92 is passed through an ultrasonic embossing station 108comprising an ultrasonic calendaring head 104 and a patterned anvil roll106. The finished product, such as a wet-wipe has enhanced qualities dueto the retention of the chemical additive 24 by the chemically treatedpulp fibers during the pulp processing. In other embodiments of thepresent invention, additional chemical additive 24 may be added to thechemically treated pulp fiber stock preparation at the manufacturingmachine 38.

[0101]FIG. 2 depicts an alternative embodiment of the present inventionin which sequential addition of the first and second water insolublechemical additives 24 and 25, respectively, are added to the dewateredfibrous web slurry 33 and/or the dried fibrous web 36. It is understoodthat the addition of the first water insoluble chemical additive 24 mayoccur any where that the second water insoluble chemical additive 25 maybe applied. It is also understood that the addition of the second waterinsoluble chemical additive 25 may occur any where that the first waterinsoluble chemical additive 24 may be applied. A fiber slurry 10 isprepared and thereafter transferred through suitable conduits (notshown) to the headbox 28 where the fiber slurry 10 is injected ordeposited into a fourdrinier section 30 thereby forming a wet fibrousweb 32. The wet fibrous web 32 may be subjected to mechanical pressureto remove process water. In the illustrated embodiment, the fourdriniersection 30 precedes a press section 44, although alternative dewateringdevices such as a nip thickening device, or the like known in the artmay be used in the pulp sheet machine. The fiber slurry 10 is depositedonto a foraminous fabric 46 such that the fourdrinier section filtrate48 is removed from the wet fibrous web 32. The fourdrinier sectionfiltrate 48 comprises a portion of the process water. The press section44 or other dewatering device suitably increases the fiber consistencyof the wet fibrous web 32 to about 30 percent or greater, andparticularly about 40 percent or greater thereby forming a dewateredfibrous web 33. The process water removed as fourdrinier sectionfiltrate 48 during the web forming step may be used as dilution waterfor dilution stages in the pulp processing or discarded.

[0102] The dewatered fibrous web 33 may be further dewatered inadditional press sections 44 or other dewatering devices known in theart. The suitably dewatered fibrous web 33 may be transferred to a dryersection 34 where evaporative drying is carried out on the dewateredfibrous web 33 to an airdry consistency, thereby forming a dried fibrousweb 36. The dried fibrous web 36 is thereafter wound on a reel 37 orslit, cut into sheets, and baled via a baler (not shown) for delivery tomanufacturing machines 38 (shown in FIG. 3).

[0103] The first water insoluble chemical additive 24 may be added orapplied to the dewatered fibrous web 33 or the dried fibrous web 36 at avariety of addition points 35 a, 35 b, 35 c, and 35 d as shown in FIG.2. It is understood that while only four addition points 35 a, 35 b, 35c, and 35 d are shown in FIG. 2, the application of the first waterinsoluble chemical additive 24 may occur at any point between the pointof initial dewatering of the wet fibrous web 32 to the point the driedfibrous web 36 is wound on the reel 37 or baled for transport to themanufacturing machines 38. The addition point 35 a shows the addition ofthe first water insoluble chemical additive 24 within press section 44.The addition point 35 b shows the addition of the first chemicaladditive 24 between the press section 44 and the dryer section 34. Theaddition point 35 c shows the addition of the first water insolublechemical additive 24 within the dryer section 34. The addition point 35d shows the addition of the first water insoluble chemical additive 24between the dryer section 34 and the reel 37 or baler.

[0104] The second water insoluble chemical additive 25 may be added orapplied to the dewatered fibrous web 33 or the dried fibrous web 36 at avariety of addition points 35 a, 35 b, 35 c, and 35 d as shown in FIG.2. It is understood that while only four addition points 35 a, 35 b, 35c, and 35 d are shown in FIG. 2, the application of the second waterinsoluble chemical additive 25 may occur at any point between the pointof initial dewatering of the wet fibrous web 32 to the point the driedfibrous web 36 is wound on the reel 37 or baled for transport to themanufacturing machines 38 downstream of at least the initial point ofapplication of the first water insoluble chemical additive 24. Theaddition point 35 a shows the addition of the second water insolublechemical additive 25 within press section 44. The addition point 35 bshows the addition of the second water insoluble chemical additive 25between the press section 44 and the dryer section 34. The additionpoint 35 c shows the addition of the second chemical additive within thedryer section 34. The addition point 35 d shows the addition of thesecond water insoluble chemical additive 25 between the dryer section 34and the reel 37 or baler.

[0105] At the manufacturing machines 38, one example of such machines 38is shown in FIG. 3, a primary gas stream 66 containing polymericmicrofibers, formed by any known method, such as meltblown techniques.The molten polymeric material is extruded through a diehead 68 byconverging flows of high velocity heated gas (usually air) supplied fromnozzles 70 and 72. The primary gas stream 66 is merged with a secondarygas stream 74 containing individualized chemically treated pulp fibershaving the chemical additives 24 and 25 so as to integrate the twodifferent fibrous materials into a single integrated stream 76 in asingle step. The manufacturing machine 38 typically includes aconventional picker roll 78 having teeth for divellicating pulp sheets80 into individual chemically treated pulp fibers having the chemicaladditives 24 and 25. The chemically treated pulp sheets 80 having thechemical additives 24 and 25 are fed radially by means of rolls 82. Theindividualized chemically treated pulp fibers having the chemicaladditives 24 and 25 are conveyed downwardly toward the primary airstream 66 through a forming nozzle or duct 84. A housing 86 encloses thepicker roll 78 and provides a passage 88 between the housing 86 and thesurface of the picker roll 78. The secondary gas stream 74 suppliedthrough duct 90 passes through the passage 88 while carrying theindividualized chemically treated pulp fibers having the chemicaladditives 24 and 25 through the forming nozzle 84. To convert thefibrous blend in the integrated stream 76 into an integral fibrousnon-woven material or fibrous non-woven composite material 92, theintegrated stream 76 passes through a nip of a pair of vacuum rolls 94and 96 having foraminous surfaces that rotate continuously over a pairof fixed vacuum nozzles 98 and 100. As the integrated stream 76 ispulled into the vacuum nozzles 98 and 100, the carrying gas is removedwhile the fibrous blend is supported and slightly compressed by theopposed surfaces of the two rolls 94 and 96. The integral fibrousnon-woven material or fibrous non-woven composite material 92 removedfrom the vacuum roll nip and conveyed to a wind-up roll 102. Theintegral fibrous non-woven material or fibrous non-woven compositematerial 92 is passed through an ultrasonic embossing station 108comprising an ultrasonic calendaring head 104 and a patterned anvil roll106. The finished product, such as a wet-wipe has enhanced qualities dueto the retention of the chemical additives 24 and 25 by the chemicallytreated pulp fibers during the pulp processing. In other embodiments ofthe present invention, additional chemical additives 24 and 25 may beadded to the chemically treated pulp fiber stock preparation at themanufacturing machine 38.

[0106] In other embodiments, it is understood that a third, fourth,fifth, so forth, water insoluble chemical additives may be used to treatthe dewatered fibrous web 33 and/or dried fibrous web 36.

[0107] The amount of first water insoluble chemical additive 24 issuitably about 0.1 kg./metric ton of pulp fiber or greater. Inparticular embodiments, the first water insoluble chemical additive 24is a polysiloxane and is added in an amount from about 0.1 kg./metricton of pulp fiber or greater.

[0108] The amount of the second water insoluble chemical additive 25 issuitably about 0.1 kg./metric ton of pulp fiber or greater. Inparticular embodiments, the second water insoluble chemical additive 25is a polysiloxane and is added in an amount from about 0.1 kg./metricton of pulp fiber or greater.

[0109] In other embodiments of the present invention, each of the firstand second water insoluble chemical additives 24 and 25 may be added tothe fiber slurry 10 at a variety of positions in the pulp processingapparatus.

[0110] In other embodiments of the present invention, one batch of pulpfibers may be treated with a first water insoluble chemical additive 24according to the method of the present invention as discussed abovewhile a second batch of pulp fibers may be treated with a second waterinsoluble chemical additive 25 according to the present invention.During the manufacturing process, different pulp fibers or pulp fibershaving different treatments may be processed into a layered or pliedfibrous non-woven material or a layered or plied product made therefrom.

[0111] In other embodiments of the present invention, a gradient of thefirst and/or the second water insoluble chemical additives 24 and 25along the z-direction of the dewatered fibrous web 33 and/or the driedfibrous web 36 may be established by a directed application of the firstand/or the second water insoluble chemical additives 24 and 25. In oneembodiment, the first and/or the second water insoluble chemicaladditives 24 and 25 are applied to one side of the dewatered fibrous web33 and/or the dried fibrous web 36. In another embodiment, one side ofthe dewatered fibrous web 33 and/or the dried fibrous web 36 issaturated with the first and/or the second water insoluble chemicaladditives 24 and 25. In another embodiment, a dual gradient may beestablished in the z-direction of the dewatered fibrous web 33 and/orthe dried fibrous web 36 by applying the first water insoluble chemicaladditive 24 to one side of the dewatered fibrous web 33 and/or the driedfibrous web 36 and applying the second water insoluble chemical additive25 to the other (opposing) side of the dewatered fibrous web 33 and/orthe dried fibrous web 36. The term “z-direction” refers to the directionthrough the thickness of the web material.

[0112] The first and/or the second water insoluble chemical additives 24and 25 may be applied so as to establish a gradient wherein about 100percent of each of the first and/or the second water insoluble chemicaladditives 24 and 25 is located from the side of the dewatered fibrousweb 33 and/or the dried fibrous web 36 treated with the first and/or thesecond water insoluble chemical additives 24 and 25 to the middle of thedewatered fibrous web 33 and/or the dried fibrous web 36 along thez-direction of the dewatered fibrous web 33 and/or the dried fibrous web36 and substantially none of each of the first and/or the second waterinsoluble chemical additives 24 and 25 is located from the middle of thedewatered fibrous web 33 and/or the dried fibrous web 36 to the opposingside of the dewatered fibrous web 33 and/or the dried fibrous web 36along the z-direction of the dewatered fibrous web 33 and/or the driedfibrous web 36.

[0113] The first and/or the second water insoluble chemical additives 24and 25 may be applied so as to establish a gradient wherein about 66percent of each of the first and/or the second water insoluble chemicaladditives 24 and 25 is located from the side of the dewatered fibrousweb 33 and/or the dried fibrous web 36 treated with the first and/or thesecond water insoluble chemical additives 24 and 25 to the middle of thedewatered fibrous web 33 and/or the dried fibrous web 36 along thez-direction of the dewatered fibrous web 33 and/or the dried fibrous web36 and about 33 percent of each of the first and/or the second waterinsoluble chemical additives 24 and 25 is located from the middle of thedewatered fibrous web 33 and/or the dried fibrous web 36 to the opposingside of the dewatered fibrous web 33 and/or the dried fibrous web 36along the z-direction of the dewatered fibrous web 33 and/or the driedfibrous web 36. The gradient may also be established wherein about 100percent, about 75 percent, about 60 percent, about 50 percent, about 40percent, about 25 percent, or about 0 percent of each of the firstand/or second water insoluble chemical additives 24 and 25 is locatedfrom one side of the dewatered fibrous web 33 and/or the dried fibrousweb 36 and about 0 percent, about 25 percent, about 40 percent, about 50percent, about 60 percent, about 75 percent, or about 100 percent ofeach of the first and/or second water insoluble chemical additives 24and 25 is located from the opposing side of the dewatered fibrous web 33and/or the dried fibrous web 36.

[0114] It is understood that in any of these embodiments, the first andsecond water insoluble chemical additives 24 and 25 may be each appliedon opposing sides of the dewatered fibrous web 33 and/or the driedfibrous web 36. Alternatively, the first and second water insolublechemical additives 24 and 25 could be applied to both opposing sides ofthe dewatered fibrous web 33 and/or the dried fibrous web 36. In stillanother variation, the first and second water insoluble chemicaladditives 24 and 25 could be applied to only one side of the dewateredfibrous web 33 and/or the dried fibrous web 36. Where only a first waterinsoluble chemical additive 24 is applied to the dewatered fibrous web33 and/or the dried fibrous web 36, the first water insoluble chemicaladditive 24 may be applied to one side or both opposing sides of thedewatered fibrous web 33 and/or the dried fibrous web 36

[0115] In another embodiment of the present invention, the amounts ofthe first and/or second water insoluble chemical additives 24 and 25 maybe reduced from typical amounts while still imparting unique productcharacteristics due to the distribution of the first and/or second waterinsoluble chemical additives 24 and 25 on or within the dewateredfibrous web 33 and/or the dried fibrous web 36 as opposed to anembodiment of the present invention wherein an equilibrated distributionof the first and/or second water insoluble chemical additives 24 and 25of the dewatered fibrous web 33 and/or the dried fibrous web 36. Theestablishment of a gradient of the application of the first and/or thesecond water insoluble chemical additives 24 and 25 of the dewateredfibrous web 33 and/or the dried fibrous web 36 is one way in which thismay be accomplished.

[0116] A directed application of a water insoluble chemical additive totreat only a portion of the pulp fibers according to the presentinvention may result in a product produced having differentcharacteristics than a product having uniformly chemically treatedfibers. Additionally, directed applications typically require a loweramount of the water insoluble chemical additive to achieve paperenhancement, thereby minimizing the detrimental effects that result fromunretained water insoluble chemical additives in the manufacturing watersystems or in the solutions that may be used with finished products.

[0117] A wide variety of fluidized bed coating systems can be adapted tocoat or treat pulp fibers with a water insoluble chemical additive thatenhances the properties of the pulp fibers or the properties of the pulpfibers during the process or methods of making chemically treatedfibrous non-woven materials or finished products made therefrom. Forexample, one can use a Wurster Fluid Bed Coater such as the Ascoat UnitModel 101 of Lasko Co. (Leominster, Mass.), the Magnacoater®) by FluidAir, Inc. (Aurora, Ill.), or the modified Wurster coater described inU.S. Pat. No. 5,625,015 issued Apr. 29, 1997 to Brinen et al., hereinincorporated by reference. The Wurster fluidized bed coating technology,one of the most popular methods for particle coating, was originallydeveloped for the encapsulation of solid particulate materials such aspowders, granules, and crystals, but according to the present invention,can be adapted to deliver a coating of at least one water insolublechemical additive to the pulp fibers.

[0118] The coater is typically configured as a cylindrical or taperedvessel (larger diameter at the top than at the bottom) with airinjection at the bottom through air jets or a distributor plate havingmultiple injection holes. The pulp fibers are fluidized in the gaseousflow. One or more spray nozzles inject the water insoluble chemicaladditive initially provided as a liquid, slurry, or foam at a pointwhere good contact with the moving pulp fibers can be achieved. The pulpfibers move upwards and descend behind a wall or barrier, from whencethe pulp fibers can be guided to again enter the fluidized bed and becoated (treated) again, treated with a second water insoluble chemicaladditive, or can be removed and further processed. The pulp fibers mayalso be treated simultaneously with two or more water insoluble chemicaladditives using one or more nozzles. Ambient dry air or elevated airtemperature or the application of other forms of energy (microwaves,infrared radiation, electron beams, ultraviolet radiation, steam, andthe like) causes drying or curing of the chemical additive on the pulpfibers. The retention time of the pulp fibers in the fluidized bed aplurality of times to provides the desired amount of treatment of one ormore water insoluble chemical additives on the pulp fibers.

[0119] The original Wurster fluid bed coaters are described in U.S. Pat.No. 2,799,241 issued Jul. 16, 1957 to D. E. Wurster; U.S. Pat. No.3,089,824 issued May 14, 1963 to D. E. Wurster; U.S. Pat. No. 3,117,024issued Jan. 7, 1964 to J. A. Lindlof et al.; U.S. Pat. No. 3,196,827issued Jul. 27, 1965 to D. E. Wurster and J. A. Lindlof; U.S. Pat. No.3,207,824 issued Sep. 21, 1965 to D. E. Wurster et al.; U.S. Pat. No.3,241,520 issued Mar. 21, 1966 to D. E. Wurster and J. A. Lindlof; and,U.S. Pat. No. 3,253,944 issued May 31, 1966 to D. E. Wurster; all ofwhich are herein incorporated by reference. More recent examples of theuse of Wurster coaters are given in U.S. Pat. No. 4,623,588 issued Nov.18, 1986 to Nuwayser et al., herein incorporated by reference. A relateddevice is the coater is disclosed in U.S. Pat. No. 5,254,168 issued Oct.19, 1993 to Littman et al., herein incorporated by reference.

[0120] Other coating methods need not rely on particle fluidization ofthe pulp fibers in a gas stream. The pulp fibers may be sprayed ortreated with one or more water insoluble chemical additives while beingmechanically agitated by a shaker or other pulsating device during themanufacturing process, such as while the pulp fibers are dropped fromone container to another, while the pulp fibers are tumbled in a movingvessel or a vessel with rotating paddles such as a Forberg particlecoater (Forberg AS, Larvik, Norway) which can be operated withoutapplied vacuum to keep the water insoluble chemical additives on thesurface of the pulp fibers, or while the pulp fibers rest in a bed,after which the pulp fibers may be separated or broken up. In oneembodiment, pulp fibers and a water insoluble chemical additive may befirst combined and then the pulp fibers are separated into individuallycoated (treated) pulp fibers by centrifugal forces, as disclosed in U.S.Pat. No. 4,675,140 issued Jun. 23, 1987 to Sparks et al., hereinincorporated by reference.

[0121] Systems for coating dry particles can also be adapted for pulpfibers according to the present invention. Examples of such equipmentinclude:

[0122] Magnetically Assisted Impaction Coating (MAIC) by Aveka Corp.(Woodbury, Minn.), wherein magnetic particles in a chamber are agitatedby varying magnetic fields, causing target particles and coatingmaterials to repeatedly collide, resulting in the coating of the targetparticles;

[0123] Mechanofusion by Hosokawa Micron Corp. (Hirakata, Osaka, Japan),wherein particles and coating materials in a rotating drum areperiodically forced into a gap beneath an arm pad, causing the materialsto become heated and joined together to form coated particles, a processthat is particularly effective when a thermoplastic material isinvolved;

[0124] the Theta Composer of Tokuju Corporation (Hiratsuka, Japan),wherein particles and coating material are mechanically brought togetherby a pair of rotating elliptical heads;

[0125] Henschel mixers from Thyssen Henschel Industritechnik (Kassel,Germany), believed to be useful for combining particles with polymericmaterials;

[0126] the Hybridizer of Nara Machinery (Tokyo, Japan), which employsblades rotating at high speed to impact a coating powder onto particlescarried by an air stream; and,

[0127] the Rotary Fluidized Bed Coater of the New Jersey Institute ofTechnology, which comprises a porous rotating cylinder with particlesinside. Pressurized air enters the walls of the cylinder and flowstoward a central, internal exit port. Air flow through the walls of thechamber can fluidize the particles, acting against centrifugal force. Asthe particles are fluidized, a coating material injected into thechamber can impinge upon the particles and coat them.

[0128] With dry particle coating systems, the pulp fibers may first betreated with a first water insoluble chemical additive by any technique,and then subsequently treated with a second water insoluble chemicaladditive in powder form. The pulp fibers may also be treated with thefirst and second water insoluble chemical additives simultaneously.Doing so creates a coating treatment in which the second water insolublechemical additive is selectively distributed near the exterior surfaceof the coating treatment, and in which the portion of the coatingtreatment next to the pulp fibers may be substantially free of thesecond water insoluble chemical additive.

[0129] By way of example, FIGS. 4 and 5 illustrate two versions of afluidized bed coating process that can be used to coat pulp fibers 130according to the present invention. In FIG. 4, the depicted apparatus120 comprises an inner cylindrical partition 122, an outer cylindricalpartition 124, and a distributor plate 126 having a central porous orsintered region for injection of gas to entrain pulp fibers 130. Themajority of the fluidizing gas flow is directed through the innercylindrical partition 122. Thus, the general flow pattern of the pulpfibers 130 is upward inside the inner cylindrical partition 122, anddownward outside the inner cylindrical partition 122. Unlike severalcommon versions of the Wurster process, in the apparatus 120 of FIG. 4,the spray nozzle 128 is located at the bottom of the apparatus 120, justabove the distributor plate 126. The nozzle 128 sprays upward, providinga cocurrent application of a spray 132 of a water insoluble chemicaladditive to the pulp fibers 130. Any suitable spray nozzle and deliverysystem known in the art can be used.

[0130]FIG. 5 is similar to FIG. 4 except that the inner cylindricalpartition 122 of FIG. 4 has been removed, and the porous or sinteredregion of the distributor plate 126 now substantially extends over theentire distributor plate 126.

[0131] Many aspects of the apparatus in FIG. 4 can be modified withinthe scope of the present invention. For example, the inner cylindricalpartition 122 may be replaced with one or more baffles or flow guides(not shown). The walls of either the outer cylindrical partition 124 orinner cylindrical partition 122 may be tapered and may be interruptedwith ports or openings for removal of the pulp fibers 130 or addition ofa water insoluble chemical additive from one or more spray nozzles (notshown). Either the outer cylindrical partition 124 or the innercylindrical partition 122 or both may rotate, vibrate, or oscillate. Thedistributor plate 126 may also move during the treatment operation(e.g., vibrate, rotate, or oscillate). A variety of spray nozzles anddelivery systems can be applied to deliver the coating material,including the Silicone Dispensing System of GS Manufacturing (CostaMesa, Calif.). The water insoluble chemical additives can be applied byspraying from any position in the apparatus 120, or by curtain coatingor slot coating or other processes applied to a moving stream of pulpfibers 130.

[0132] While the invention has been described in conjunction withspecific embodiments, it is to be understood that many alternatives,modifications and variations will be apparent to those skilled in theart in light of the foregoing description. Accordingly, this inventionis intended to embrace all such alternatives, modifications andvariations, which fall within the spirit and scope of the appendedclaims.

We claim:
 1. A method for preparing chemically treated pulp fiberscomprising: a) creating a fiber slurry comprising process water andvirgin pulp fibers; b) transporting the fiber slurry to a web-formingapparatus of a pulp sheet machine and forming a wet fibrous web; c)drying the wet fibrous web to a predetermined consistency therebyforming a dried fibrous web; d) treating the dried fibrous web with awater insoluble chemical additive thereby forming a chemically treateddried fibrous web containing chemically treated pulp fibers, wherein thechemically treated pulp fibers have an improved level of chemicalretention of the water insoluble chemical additive and retain frombetween about 25 to about 100 percent of the applied amount of the waterinsoluble chemical additive when the chemically treated pulp fibers areexposed to a liquid; and, e) using the chemically treated pulp fibershaving the water insoluble chemical additive retained thereon to form afibrous non-woven material.
 2. The method of claim 1, wherein thefibrous non-woven material is coform.
 3. The method of claim 1, whereinthe dried chemically treated fibrous web includes a gradient of thewater insoluble chemical additive.
 4. The method of claim 1, furthercomprising dewatering the wet fibrous web thereby forming a dewateredfibrous web.
 5. The method of claim 4, further comprising drying thedewatered fibrous web thereby forming the dried fibrous web.
 6. Themethod of claim 5, wherein the fibrous non-woven material comprisespolypropylene.
 7. The method of claim 2, further comprising producing afinished product having enhanced quality due to the retention of thewater insoluble chemical additive by the chemically treated pulp fibers.8. The method of claim 1, wherein the water insoluble chemical additiveis selected from the group comprising softening agents, dry strengthagents, wet strength agents, opacifying agents, dyes, debonding agents,absorbency agents, sizing agents, optical brighteners, chemical tracers,and mixtures thereof.
 9. The method of claim 1, wherein the waterinsoluble chemical additive is selected from the group consisting of:mineral oil; petrolatum; olefins; alcohols; fatty alcohols; ethoxylatedfatty alcohols; esters; high molecular weight carboxylic andpolycarboxylic acids and their salts; polydimethylsiloxane and modifiedpolydimethylsiloxane; and, mixtures thereof.
 10. The method of claim 1,wherein the fibrous non-woven material comprises at least 2 plies. 11.The method of claim 1, wherein the water insoluble chemical additive isapplied to the dried fibrous web in an amount of at least about 0.1kilograms per metric ton or greater.
 12. The method of claim 1, whereinthe fibrous non-woven material comprises at least 2 layers.
 13. Themethod of claim 1, wherein sufficient residence time is provided afterthe water insoluble chemical additive is applied to the dried fibrousweb to allow for retention of the water insoluble chemical additive bythe chemically treated pulp fiber of the dried fibrous web.
 14. Themethod of claim 1, further comprising forming a wet-wipe product fromthe chemically treated dried fibrous web.
 15. A wet-wipe product madeusing the method of claim
 1. 16. The wet-wipe product of claim 15,wherein the amount of the water insoluble chemical additive applied tothe dried fibrous web is about 0.1 kilogram per metric ton or greater.17. A method for applying a water insoluble chemical additive to afibrous non-woven material, the method comprising: a) mixing pulp fiberswith process water to form a pulp fiber slurry; b) transporting thefiber slurry to a web-forming apparatus of a pulp sheet machine andforming a wet fibrous web; c) dewatering the wet fibrous web to apredetermined consistency thereby forming a dewatered fibrous web; d)applying a water insoluble chemical additive to the dewatered fibrousweb thereby forming a chemically treated dewatered fibrous webcontaining chemically treated pulp fibers, wherein the chemicallytreated pulp fibers have an improved level of chemical retention of thewater insoluble chemical additive and retain from between about 25 toabout 100 percent of the applied amount of the water insoluble chemicaladditive when the chemically treated pulp fibers are exposed to aliquid; and, e) using the chemically treated pulp fibers having thewater insoluble chemical additive retained thereon to form a fibrousnon-woven material.
 18. The method of claim 17, further comprisingtransporting the chemically treated dewatered fibrous web to amanufacturing machine and mixing the chemically treated pulp fiberhaving the water insoluble chemical additive retained thereon with athermoplastic polymeric material.
 19. The method of claim 17, whereinthe chemically treated dewatered fibrous web includes a gradient of thenon-watered soluble chemical additive.
 20. The method of claim 17,further comprising drying the chemically treated dewatered fibrous webto a predetermined consistency thereby forming a chemically treateddried fibrous web.
 21. The method of claim 20, wherein the chemicallytreated dried fibrous web includes a gradient of the water insolublechemical additive.
 22. The method of claim 20, wherein said fibrousnon-woven material comprises polypropylene.
 23. The method of claim 22,further comprising forming a finished product having enhanced qualitydue to the retention of the water insoluble chemical additive by thechemically treated pulp fibers.
 24. The method of claim 22, wherein theamount of the water insoluble chemical additive retained by thechemically treated pulp fibers is about 0.1 kilogram per metric ton orgreater, and the amount of unretained the water insoluble chemicaladditive in the water is between 0 and about 50 percent of the amount ofthe applied water insoluble chemical additive retained by the chemicallytreated dried fibrous web.
 25. The method of claim 17, wherein theamount of the water insoluble chemical additive applied to the dewateredfibrous web is about 1 kilograms per metric ton or greater.
 26. Themethod of claim 17, wherein the amount of the water insoluble chemicaladditive applied to the dewatered fibrous web is about 3 kilograms permetric ton or greater.
 27. The method of claim 17, wherein the amount ofthe water insoluble chemical additive applied to the dewatered fibrousweb is about 5 kilograms per metric ton or greater.
 28. The method ofclaim 17, wherein the water insoluble chemical additive is selected fromthe group comprising softening agents, dry strength agents, wet strengthagents, opacifying agents, dyes, debonding agents, absorbency agents,sizing agents, optical brighteners, chemical tracers, and mixturesthereof.
 29. The method of claim 17, wherein the water insolublechemical additive is selected from the group consisting of: mineral oil;petrolatum; olefins; alcohols; fatty alcohols; ethoxylated fattyalcohols; esters; high molecular weight carboxylic and polycarboxylicacids and their salts; polydimethylsiloxane and modifiedpolydimethylsiloxane; and, mixtures thereof.
 30. A wet-wipe product madefrom the chemically treated pulp fiber slurry of claim
 17. 31. A methodfor adding at least a first chemical additive to pulp fiber contained ina fibrous non-woven material, the method comprising: a) mixing pulpfibers with process water thereby forming a fiber slurry; b)transporting the fiber slurry to a web-forming apparatus of a pulp sheetmachine; c) dewatering the fiber slurry thereby forming a crumb pulp; d)applying a water insoluble chemical additive to the crumb pulp therebyforming a chemically treated crumb pulp containing chemically treatedpulp fibers, wherein the chemically treated pulp fibers have an improvedlevel of chemical retention of the water insoluble chemical additive andretain from between about 25 to about 100 percent of the applied amountof the water insoluble chemical additive when the chemically treatedpulp fibers are exposed to a liquid; and, e) using the chemicallytreated pulp fibers having the water insoluble chemical additiveretained thereon to form a fibrous non-woven material.
 32. The method ofclaim 31, further comprising transporting the chemically treated crumbpulp to a manufacturing machine and mixing the chemically treated pulpfibers having the water insoluble chemical additive retained thereonwith a thermoplastic polymeric material.
 33. The method of claim 32,further comprising transporting the chemically treated pulp fiberthrough the manufacturing machine to form a finished wet-wipe producthaving enhanced quality due to the retention of at least a firstchemical additive by the chemically treated pulp fibers.
 34. The methodof claim 31, further comprising applying a second chemical additive tothe chemically treated crumb pulp.
 35. A method for applying waterinsoluble chemical additives to pulp fiber contained in a fibrousnon-woven material, the method comprising: a) creating a fiber slurrycomprising process water and pulp fibers; b) transporting the fiberslurry to a web-forming apparatus of a pulp sheet machine and forming awet fibrous web; c) dewatering the wet fibrous web to a predeterminedconsistency thereby forming a dewatered fibrous web; d) applying a firstwater insoluble chemical additive to the dewatered fibrous web therebyforming a chemically treated dewatered fibrous web of chemically treatedpulp fibers; e) applying a second water insoluble chemical additive tothe chemically treated dewatered fibrous web thereby forming a dualchemically treated dewatered fibrous web containing dual chemicallytreated pulp fibers, wherein the dual chemically treated pulp fibershave an improved level of chemical retention of the first waterinsoluble chemical additive and retain from between about 25 to about100 percent of the applied amount of the first water insoluble chemicaladditive when the dual chemically treated pulp fibers are exposed to aliquid and wherein the dual chemically treated pulp fibers have animproved level of chemical retention of the second water insolublechemical additive and retain from between about 25 to about 100 percentof the applied amount of the second water insoluble chemical additivewhen the dual chemically treated pulp fibers are exposed to a liquid;and, f) using the dual chemically treated pulp fibers having the firstand second water insoluble chemical additives retained thereon to form afibrous non-woven material.
 36. The method of claim 35, furthercomprising transporting the dual chemically treated pulp fibers to amanufacturing machine and mixing the dual chemically treated pulp fibershaving the first and second water insoluble chemical additives retainedthereon with a thermoplastic material.
 37. The method of claim 35,further comprising drying the dual chemically treated dewatered fibrousweb to a predetermined consistency thereby forming a dual chemicallytreated dried fibrous web.
 38. The method of claim 37, furthercomprising transporting the dual chemically treated dried fibrous web toa manufacturing machine and mixing the dual chemically treated pulpfibers having the first and second water insoluble chemical additivesretained thereon with a thermoplastic polymeric material.
 39. The methodof claim 35, wherein the dual chemically treated dewatered fibrous webincludes a gradient of the first water insoluble chemical additive. 40.The method of claim 35, wherein the dual chemically treated driedfibrous web includes a gradient of the first water insoluble chemicaladditive.
 41. The method of claim 35, wherein the dual chemicallytreated dewatered fibrous web includes a gradient of the second waterinsoluble chemical additive.
 42. The method of claim 35, wherein thedual chemically treated dried fibrous web includes a gradient of thesecond water insoluble chemical additive.
 43. The method of claim 38,further comprising producing a wet-wipe product having enhanced qualitydue to the retention of the first and second water insoluble chemicaladditives by the dual chemically treated pulp fibers.
 44. The method ofclaim 35, wherein the first water insoluble chemical additive isselected from the group comprising softening agents, dry strengthagents, wet strength agents, opacifying agents, dyes, debonding agents,absorbency agents, sizing agents, optical brighteners, chemical tracers,and mixtures thereof.
 45. The method of claim 44, wherein the firstwater insoluble chemical additive is selected from the group consistingof: mineral oil; petrolatum; olefins; alcohols; fatty alcohols;ethoxylated fatty alcohols; esters; high molecular weight carboxylic andpolycarboxylic acids and their salts; polydimethylsiloxane and modifiedpolydimethylsiloxane; and, mixtures thereof.
 46. The method of claim 35,wherein the second water insoluble chemical additive is selected fromthe group comprising softening agents, dry strength agents, wet strengthagents, opacifying agents, dyes, debonding agents, absorbency agents,sizing agents, optical brighteners, chemical tracers, and mixturesthereof.
 47. The method of claim 46, wherein the second water insolublechemical additive is selected from the group consisting of: mineral oil;petrolatum; olefins; alcohols; fatty alcohols; ethoxylated fattyalcohols; esters; high molecular weight carboxylic and polycarboxylicacids and their salts; polydimethylsiloxane and modifiedpolydimethylsiloxane; and, mixtures thereof.
 48. The method of claim 35,wherein the first and second water insoluble chemical additives areapplied to the dewatered fibrous web simultaneously.
 49. The method ofclaim 35, wherein the first water insoluble chemical additive is appliedto the dewatered fibrous web in an amount of about 0.1 kilograms permetric ton or greater.
 50. The method of claim 35, wherein the secondwater insoluble chemical additive is applied to the dewatered fibrousweb in an amount of about 0.1 kilogram per metric ton or greater. 51.The method of claim 35, wherein the dual chemically treated driedfibrous web has a consistency ranging from about 65 percent to about 100percent.
 52. The method of claim 35, wherein sufficient residence timeis provided after the first water insoluble chemical additive is appliedto the dewatered fibrous web to allow the first water insoluble chemicaladditive to be retained by the dual chemically treated pulp fiber. 53.The method of claim 35, wherein sufficient residence time is providedafter the second water insoluble chemical additive is applied to thedewatered fibrous web to allow the second water insoluble chemicaladditive to be retained by the dual chemically treated pulp fiber.
 54. Awet-wipe product made using the method of claim
 35. 55. A method forapplying water insoluble chemical additives to pulp fiber contained in afibrous non-woven material, the method comprising: a) mixing pulp fiberswith process water to form a fiber slurry; b) transporting the fiberslurry to a web-forming apparatus of a pulp sheet machine and forming awet fibrous web; c) dewatering the wet fibrous web to a predeterminedconsistency thereby forming a dewatered fibrous web; d) drying thedewatered fibrous web to a predetermined consistency thereby forming adried fibrous web; e) applying a first water insoluble chemical additiveto the dried fibrous web and applying a second water insoluble chemicaladditive to the dried fibrous web thereby forming a dual chemicallytreated dried fibrous web containing dual chemically treated pulpfibers, wherein the dual chemically treated pulp fibers have an improvedlevel of chemical retention of the first water insoluble chemicaladditive and retain from between about 25 to about 100 percent of theapplied amount of the first water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid and whereinthe dual chemically treated pulp fibers have an improved level ofchemical retention of the second water insoluble chemical additive andretain from between about 25 to about 100 percent of the applied amountof the second water insoluble chemical additive when the dual chemicallytreated pulp fibers are exposed to a liquid; and, f) using the dualchemically treated pulp fibers having the first and second waterinsoluble chemical additives retained thereon to form a fibrousnon-woven material.
 56. The method of claim 55, wherein the dualchemically treated dried fibrous web includes a gradient of the firstwater insoluble chemical additive.
 57. The method of claim 55, whereinthe dual chemically treated dried fibrous web includes a gradient of thesecond water insoluble chemical additive.
 58. The method of claim 55,further comprising transporting the dual chemically treated driedfibrous web to a manufacturing machine and mixing the dual chemicallytreated pulp fibers having at least the first and second water insolublechemical additives retained thereon with a thermoplastic material. 59.The method of claim 55, further comprising transporting the dualchemically treated pulp fiber through the paper machine to form afinished wet-wipe product having enhanced quality due to the retentionof at least the first and second water insoluble chemical additives bythe dual chemically treated pulp fibers.
 60. The method of claim 58,wherein the amount of the first water insoluble chemical additiveretained by the dual chemically treated pulp fibers is about 0.1kilogram per metric ton or greater, and the amount of unretained firstwater insoluble chemical additive in the water is between 0 and about 75percent of the applied amount of the first water insoluble chemicaladditive when the dual chemically treated pulp fibers are exposed to aliquid.
 61. The method of claim 58, wherein the amount of the secondwater insoluble chemical additive retained by the dual chemicallytreated pulp fibers is about 0.1 kilogram per metric ton or greater, andthe amount of unretained second water insoluble chemical additive in thewater is between 0 and about 75 percent of the applied amount of thesecond water insoluble chemical additive when the dual chemicallytreated pulp fibers are exposed to a liquid.
 62. The method of claim 58,wherein the amount of the first water insoluble chemical additiveretained by the dual chemically treated pulp fibers is about 0.1kilograms per metric ton or greater, and the amount of unretained firstwater insoluble chemical additive in the water is between 0 and about 75percent of the applied amount of the first water insoluble chemicaladditive when the dual chemically treated pulp fibers are exposed in aliquid and wherein the amount of the second water insoluble chemicaladditive retained by the dual chemically treated pulp fibers is about0.1 kilogram per metric ton or greater, and the amount of unretainedsecond water insoluble chemical additive in the water is between 0 andabout 75 percent of the applied amount of the second water insolublechemical additive when the dual chemically treated pulp fibers areexposed in a liquid.
 63. A paper or tissue product made using the methodof claim
 55. 64. A method for applying water insoluble chemicaladditives to pulp fiber contained in a fibrous non-woven material, themethod comprising: a) mixing pulp fibers with process water to form afiber slurry; b) transporting the fiber slurry to a web-formingapparatus of a pulp sheet machine and forming a wet fibrous web; c)dewatering the wet fibrous web to a predetermined consistency therebyforming a dewatered fibrous web; d) applying a first water insolublechemical additive to the dewatered fibrous web to the dewatered fibrousweb thereby forming a chemically treated dewatered fibrous web; e)drying the chemically treated dewatered fibrous web to a predeterminedconsistency thereby forming a chemically treated dried fibrous web; f)applying a second water insoluble chemical additive to the chemicallytreated dried fibrous web, thereby forming a dual chemically treateddried fibrous web containing dual chemically treated pulp fibers,wherein the dual chemically treated pulp fibers have an improved levelof chemical retention of the first water insoluble chemical additivewherein the level of chemical retention of the first water insolublechemical additive is between about 25 to about 100 percent retention ofthe applied amount of the first water insoluble chemical additive whenthe dual chemically treated pulp fibers are exposed to a liquid and thedual chemically treated pulp fibers have an improved level of chemicalretention of the second water insoluble chemical additive wherein thelevel of chemical retention of the second water insoluble chemicaladditive is between about 25 to about 100 percent retention of theapplied amount of the second water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid; and, g)using the dual chemically treated pulp fibers having the first andsecond water insoluble chemical additives retained thereon to form afibrous non-woven material.
 65. The method of claim 64, wherein thechemically treated dewatered fibrous web includes a gradient of thefirst water insoluble chemical additive.
 66. The method of claim 64,wherein the dual chemically treated dried fibrous web includes agradient of the first water insoluble chemical additive.
 67. The methodof claim 64, wherein the dual chemically treated dried fibrous webincludes a gradient of the second water insoluble chemical additive. 68.The method of claim 64, further comprising transporting the dualchemically treated dried fibrous web to a manufacturing machine andmixing the dual chemically treated pulp fibers having at least the firstand second water insoluble chemical additives retained thereon with athermoplastic polymeric material.
 69. The method of claim 64, furthercomprising transporting the chemically treated pulp fibers through themanufacturing machine to form a finished wit-wipe product havingenhanced quality due to the retention of at least the first and secondwater insoluble chemical additives by the dual chemically treated pulpfibers.
 70. The method of claim 68, wherein the amount of the firstwater insoluble chemical additive retained by the dual chemicallytreated pulp fibers is about 0.1 kilogram per metric ton or greater, andthe amount of unretained first water insoluble chemical additive in thewater is between 0 and about 75 percent of the applied amount of thefirst water insoluble chemical additive when the dual chemically treatedpulp fibers are exposed to a liquid.
 71. The method of claim 68, whereinthe amount of the second water insoluble chemical additive retained bythe dual chemically treated pulp fibers is about 0.1 kilogram per metricton or greater, and the amount of unretained second water insolublechemical additive in the water is between 0 and about 75 percent of theapplied amount of the second water insoluble chemical additive when thedual chemically treated pulp fibers are exposed to a liquid.
 72. Themethod of claim 68, wherein the amount of the first water insolublechemical additive retained by the dual chemically treated pulp fibers isabout 0.1 kilograms per metric ton or greater, and the amount ofunretained first water insoluble chemical additive in the water isbetween 0 and about 75 percent of the applied amount of the first waterinsoluble chemical additive when the dual chemically treated pulp fibersare exposed to a liquid and wherein the amount of the second waterinsoluble chemical additive retained by the dual chemically treated pulpfibers is about 0.1 kilogram per metric ton or greater, and the amountof unretained second water insoluble chemical additive in the water isbetween 0 and about 75 percent of the applied amount of the second waterinsoluble chemical additive when the dual chemically treated pulp fibersare exposed to a liquid.
 73. A wet-wipe product made using the method ofclaim 64.